diff --git a/.eslintignore b/.eslintignore index d482f09903e5..12b3ecd9baa4 100644 --- a/.eslintignore +++ b/.eslintignore @@ -130,7 +130,6 @@ devtools/server/tests/browser/storage-*.html devtools/server/tests/browser/stylesheets-nested-iframes.html devtools/server/tests/mochitest/** devtools/server/tests/unit/** -devtools/shared/heapsnapshot/** devtools/shared/platform/content/test/test_clipboard.html devtools/shared/qrcode/tests/mochitest/test_decode.html devtools/shared/tests/mochitest/*.html diff --git a/devtools/shared/heapsnapshot/CensusUtils.js b/devtools/shared/heapsnapshot/CensusUtils.js index 36bdd2d820d7..c0ed6b92795d 100644 --- a/devtools/shared/heapsnapshot/CensusUtils.js +++ b/devtools/shared/heapsnapshot/CensusUtils.js @@ -141,8 +141,9 @@ function recursiveWalk(breakdown, edge, report, visitor) { visitor.exit(breakdown, report, edge); } else { visitor.enter(breakdown, report, edge); - for (let { edge, referent, breakdown: subBreakdown } of getReportEdges(breakdown, report)) { - recursiveWalk(subBreakdown, edge, referent, visitor); + for (let { edge: ed, referent, breakdown: subBreakdown } + of getReportEdges(breakdown, report)) { + recursiveWalk(subBreakdown, ed, referent, visitor); } visitor.exit(breakdown, report, edge); } @@ -236,8 +237,6 @@ DiffVisitor.prototype._set = function (report, edge, val) { * @overrides Visitor.prototype.enter */ DiffVisitor.prototype.enter = function (breakdown, report, edge) { - const isFirstTimeEntering = this._results === null; - const newResults = breakdown.by === "allocationStack" ? new Map() : {}; let newOther; @@ -274,8 +273,8 @@ DiffVisitor.prototype.exit = function (breakdown, report, edge) { .map(e => e.edge) .filter(e => !visited.has(e)); const results = this._resultsStack[this._resultsStack.length - 1]; - for (let edge of unvisited) { - this._set(results, edge, this._get(other, edge)); + for (let edg of unvisited) { + this._set(results, edg, this._get(other, edg)); } } @@ -376,9 +375,7 @@ exports.diff = diff; * * @return {Object} */ -const createParentMap = exports.createParentMap = function (node, - getId = node => node.id, - aggregator = Object.create(null)) { +const createParentMap = function (node, getId = n => n.id, aggregator = {}) { if (node.children) { for (let i = 0, length = node.children.length; i < length; i++) { const child = node.children[i]; @@ -386,9 +383,9 @@ const createParentMap = exports.createParentMap = function (node, createParentMap(child, getId, aggregator); } } - return aggregator; }; +exports.createParentMap = createParentMap; const BUCKET = Object.freeze({ by: "bucket" }); diff --git a/devtools/shared/heapsnapshot/DominatorTreeNode.js b/devtools/shared/heapsnapshot/DominatorTreeNode.js index 13a847fd048f..87aa16eff804 100644 --- a/devtools/shared/heapsnapshot/DominatorTreeNode.js +++ b/devtools/shared/heapsnapshot/DominatorTreeNode.js @@ -237,7 +237,7 @@ DominatorTreeNode.partialTraversal = function (dominatorTree, * * @returns {DominatorTreeNode} */ -DominatorTreeNode.insert = function (tree, path, newChildren, moreChildrenAvailable) { +DominatorTreeNode.insert = function (nodeTree, path, newChildren, moreChildrenAvailable) { function insert(tree, i) { if (tree.nodeId !== path[i]) { return tree; @@ -257,7 +257,7 @@ DominatorTreeNode.insert = function (tree, path, newChildren, moreChildrenAvaila : tree; } - return insert(tree, 0); + return insert(nodeTree, 0); }; /** diff --git a/devtools/shared/heapsnapshot/HeapAnalysesWorker.js b/devtools/shared/heapsnapshot/HeapAnalysesWorker.js index d07d67f80eed..bb1ad28c41e7 100644 --- a/devtools/shared/heapsnapshot/HeapAnalysesWorker.js +++ b/devtools/shared/heapsnapshot/HeapAnalysesWorker.js @@ -8,6 +8,8 @@ // HeapAnalysesWorker is owned and communicated with by a HeapAnalysesClient // instance. See HeapAnalysesClient.js. +/* global importScripts, workerHelper, self */ + "use strict"; importScripts("resource://gre/modules/workers/require.js"); @@ -70,7 +72,8 @@ workerHelper.createTask(self, "deleteHeapSnapshot", ({ snapshotFilePath }) => { /** * @see HeapAnalysesClient.prototype.takeCensus */ -workerHelper.createTask(self, "takeCensus", ({ snapshotFilePath, censusOptions, requestOptions }) => { +workerHelper.createTask(self, "takeCensus", ( +{ snapshotFilePath, censusOptions, requestOptions }) => { if (!snapshots[snapshotFilePath]) { throw new Error(`No known heap snapshot for '${snapshotFilePath}'`); } @@ -206,7 +209,7 @@ workerHelper.createTask(self, "getDominatorTree", request => { maxRetainingPaths, } = request; - if (!(0 <= dominatorTreeId && dominatorTreeId < dominatorTrees.length)) { + if (!(dominatorTreeId >= 0 && dominatorTreeId < dominatorTrees.length)) { throw new Error( `There does not exist a DominatorTree with the id ${dominatorTreeId}`); } @@ -252,7 +255,7 @@ workerHelper.createTask(self, "getImmediatelyDominated", request => { maxRetainingPaths, } = request; - if (!(0 <= dominatorTreeId && dominatorTreeId < dominatorTrees.length)) { + if (!(dominatorTreeId >= 0 && dominatorTreeId < dominatorTrees.length)) { throw new Error( `There does not exist a DominatorTree with the id ${dominatorTreeId}`); } diff --git a/devtools/shared/heapsnapshot/census-tree-node.js b/devtools/shared/heapsnapshot/census-tree-node.js index b041e77f9c08..2ffe69b8b05f 100644 --- a/devtools/shared/heapsnapshot/census-tree-node.js +++ b/devtools/shared/heapsnapshot/census-tree-node.js @@ -74,6 +74,7 @@ CensusTreeNodeCacheValue.prototype = null; * The unique string that can be used as a key in a CensusTreeNodeCache. */ CensusTreeNodeCache.hashFrame = function (frame) { + // eslint-disable-next-line max-len return `FRAME,${frame.functionDisplayName},${frame.source},${frame.line},${frame.column},${frame.asyncCause}`; }; diff --git a/devtools/shared/heapsnapshot/shortest-paths.js b/devtools/shared/heapsnapshot/shortest-paths.js index 2d97b7de93c9..75ec26eb6368 100644 --- a/devtools/shared/heapsnapshot/shortest-paths.js +++ b/devtools/shared/heapsnapshot/shortest-paths.js @@ -48,6 +48,7 @@ exports.deduplicatePaths = function (target, paths) { nameSet.add(name); } + // eslint-disable-next-line no-labels outer: for (let path of paths) { const pathLength = path.length; @@ -57,6 +58,7 @@ exports.deduplicatePaths = function (target, paths) { predecessorsSeen.add(target); for (let i = 0; i < pathLength; i++) { if (predecessorsSeen.has(path[i].predecessor)) { + // eslint-disable-next-line no-labels continue outer; } predecessorsSeen.add(path[i].predecessor); diff --git a/devtools/shared/heapsnapshot/tests/mochitest/.eslintrc.js b/devtools/shared/heapsnapshot/tests/mochitest/.eslintrc.js new file mode 100644 index 000000000000..de11530dc72e --- /dev/null +++ b/devtools/shared/heapsnapshot/tests/mochitest/.eslintrc.js @@ -0,0 +1,10 @@ +"use strict"; + +module.exports = { + // Extend from the shared list of defined globals for mochitests. + "extends": "../../../../.eslintrc.mochitests.js", + "globals": { + "ChromeUtils": true, + "sendAsyncMessage": true, + } +}; diff --git a/devtools/shared/heapsnapshot/tests/mochitest/test_DominatorTree_01.html b/devtools/shared/heapsnapshot/tests/mochitest/test_DominatorTree_01.html index 1f9d8c080b46..3f16109a8f73 100644 --- a/devtools/shared/heapsnapshot/tests/mochitest/test_DominatorTree_01.html +++ b/devtools/shared/heapsnapshot/tests/mochitest/test_DominatorTree_01.html @@ -12,8 +12,11 @@ Sanity test that we can compute dominator trees from a heap snapshot in a web wi 
 
+        info("Loading iframe");
+        document.body.appendChild(iframe);
+      });
+    };
+  
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/Census.jsm b/devtools/shared/heapsnapshot/tests/unit/Census.jsm
index f8fb1ce444a3..11a32b1a5c43 100644
--- a/devtools/shared/heapsnapshot/tests/unit/Census.jsm
+++ b/devtools/shared/heapsnapshot/tests/unit/Census.jsm
@@ -2,6 +2,8 @@
 // Debugger.Memory.prototype.takeCensus and
 // HeapSnapshot.prototype.takeCensus. Adapted from js/src/jit-test/lib/census.js.
 
+"use strict";
+
 this.EXPORTED_SYMBOLS = ["Census"];
 
 this.Census = (function () {
@@ -62,7 +64,11 @@ this.Census = (function () {
   Census.assertAllZeros = {
     enter: () => Census.assertAllZeros,
     done: () => undefined,
-    check: elt => { if (elt !== 0) throw new Error("Census mismatch: expected zero, found " + elt); }
+    check: elt => {
+      if (elt !== 0) {
+        throw new Error("Census mismatch: expected zero, found " + elt);
+      }
+    }
   };
 
   function expectedObject() {
@@ -89,27 +95,27 @@ this.Census = (function () {
   function makeBasisChecker({compare, missing, extra}) {
     return function makeWalker(basis) {
       if (typeof basis === "object") {
-        var unvisited = new Set(Object.getOwnPropertyNames(basis));
+        let unvisited = new Set(Object.getOwnPropertyNames(basis));
         return {
           enter: prop => {
             unvisited.delete(prop);
             if (prop in basis) {
               return makeWalker(basis[prop]);
-            } else {
-              return extra(prop);
             }
+
+            return extra(prop);
           },
 
           done: () => unvisited.forEach(prop => missing(prop, basis[prop])),
           check: expectedObject
         };
-      } else {
-        return {
-          enter: expectedLeaf,
-          done: expectedLeaf,
-          check: elt => compare(elt, basis)
-        };
       }
+
+      return {
+        enter: expectedLeaf,
+        done: expectedLeaf,
+        check: elt => compare(elt, basis)
+      };
     };
   }
 
@@ -118,13 +124,18 @@ this.Census = (function () {
   }
 
   function extraProp(prop) {
-    throw new Error("Census mismatch: subject has property not present in basis: " + prop);
+    throw new Error("Census mismatch: subject has property not present in basis: "
+      + prop);
   }
 
   // Return a walker that checks that the subject census has counts all equal to
   // |basis|.
   Census.assertAllEqual = makeBasisChecker({
-    compare: (a, b) => { if (a !== b) throw new Error("Census mismatch: expected " + a + " got " + b);},
+    compare: (a, b) => {
+      if (a !== b) {
+        throw new Error("Census mismatch: expected " + a + " got " + b);
+      }
+    },
     missing: missingProp,
     extra: extraProp
   });
@@ -155,7 +166,7 @@ this.Census = (function () {
   // items of each category of the count in |basis|.
   Census.assertAllWithin = function (fudge, basis) {
     return makeBasisChecker({
-      compare: (subject, basis) => ok(Math.abs(subject - basis) <= fudge),
+      compare: (subject, base) => ok(Math.abs(subject - base) <= fudge),
       missing: missingProp,
       extra: () => Census.walkAnything
     })(basis);
diff --git a/devtools/shared/heapsnapshot/tests/unit/Match.jsm b/devtools/shared/heapsnapshot/tests/unit/Match.jsm
index c29e6484e7b3..983693a4239b 100644
--- a/devtools/shared/heapsnapshot/tests/unit/Match.jsm
+++ b/devtools/shared/heapsnapshot/tests/unit/Match.jsm
@@ -3,188 +3,212 @@
 // Ported from js/src/tests/js1_8_5/reflect-parse/Match.js for use with devtools
 // server xpcshell tests.
 
+"use strict";
+
 this.EXPORTED_SYMBOLS = ["Match"];
 
-this.Match = (function() {
-
-    function Pattern(template) {
-        // act like a constructor even as a function
-        if (!(this instanceof Pattern))
-            return new Pattern(template);
-
-        this.template = template;
+this.Match = (function () {
+  function Pattern(template) {
+      // act like a constructor even as a function
+    if (!(this instanceof Pattern)) {
+      return new Pattern(template);
     }
 
-    Pattern.prototype = {
-        match: function(act) {
-            return match(act, this.template);
-        },
+    this.template = template;
+  }
 
-        matches: function(act) {
-            try {
-                return this.match(act);
-            }
-            catch (e if e instanceof MatchError) {
-                return false;
-            }
-        },
+  Pattern.prototype = {
+    match: function (act) {
+      return match(act, this.template);
+    },
 
-        assert: function(act, message) {
-            try {
-                return this.match(act);
-            }
-            catch (e if e instanceof MatchError) {
-                throw new Error((message || "failed match") + ": " + e.message);
-            }
-        },
-
-        toString: () => "[object Pattern]"
-    };
-
-    Pattern.ANY = new Pattern;
-    Pattern.ANY.template = Pattern.ANY;
-
-    Pattern.NUMBER = new Pattern;
-    Pattern.NUMBER.match = function (act) {
-      if (typeof act !== 'number') {
-        throw new MatchError("Expected number, got: " + quote(act));
+    matches: function (act) {
+      try {
+        return this.match(act);
+      } catch (e) {
+        if (e instanceof MatchError) {
+          return false;
+        }
       }
-    }
+      return false;
+    },
 
-    Pattern.NATURAL = new Pattern
-    Pattern.NATURAL.match = function (act) {
-      if (typeof act !== 'number' || act !== Math.floor(act) || act < 0) {
-        throw new MatchError("Expected natural number, got: " + quote(act));
+    assert: function (act, message) {
+      try {
+        return this.match(act);
+      } catch (e) {
+        if (e instanceof MatchError) {
+          throw new Error((message || "failed match") + ": " + e.message);
+        }
       }
+      return false;
+    },
+
+    toString: () => "[object Pattern]"
+  };
+
+  Pattern.ANY = new Pattern();
+  Pattern.ANY.template = Pattern.ANY;
+
+  Pattern.NUMBER = new Pattern();
+  Pattern.NUMBER.match = function (act) {
+    if (typeof act !== "number") {
+      throw new MatchError("Expected number, got: " + quote(act));
+    }
+  };
+
+  Pattern.NATURAL = new Pattern();
+  Pattern.NATURAL.match = function (act) {
+    if (typeof act !== "number" || act !== Math.floor(act) || act < 0) {
+      throw new MatchError("Expected natural number, got: " + quote(act));
+    }
+  };
+
+  let quote = uneval;
+
+  function MatchError(msg) {
+    this.message = msg;
+  }
+
+  MatchError.prototype = {
+    toString: function () {
+      return "match error: " + this.message;
+    }
+  };
+
+  function isAtom(x) {
+    return (typeof x === "number") ||
+        (typeof x === "string") ||
+        (typeof x === "boolean") ||
+        (x === null) ||
+        (typeof x === "object" && x instanceof RegExp);
+  }
+
+  function isObject(x) {
+    return (x !== null) && (typeof x === "object");
+  }
+
+  function isFunction(x) {
+    return typeof x === "function";
+  }
+
+  function isArrayLike(x) {
+    return isObject(x) && ("length" in x);
+  }
+
+  function matchAtom(act, exp) {
+    if ((typeof exp) === "number" && isNaN(exp)) {
+      if ((typeof act) !== "number" || !isNaN(act)) {
+        throw new MatchError("expected NaN, got: " + quote(act));
+      }
+      return true;
     }
 
-    var quote = uneval;
-
-    function MatchError(msg) {
-        this.message = msg;
+    if (exp === null) {
+      if (act !== null) {
+        throw new MatchError("expected null, got: " + quote(act));
+      }
+      return true;
     }
 
-    MatchError.prototype = {
-        toString: function() {
-            return "match error: " + this.message;
+    if (exp instanceof RegExp) {
+      if (!(act instanceof RegExp) || exp.source !== act.source) {
+        throw new MatchError("expected " + quote(exp) + ", got: " + quote(act));
+      }
+      return true;
+    }
+
+    switch (typeof exp) {
+      case "string":
+        if (act !== exp) {
+          throw new MatchError("expected " + quote(exp) + ", got " + quote(act));
         }
-    };
-
-    function isAtom(x) {
-        return (typeof x === "number") ||
-            (typeof x === "string") ||
-            (typeof x === "boolean") ||
-            (x === null) ||
-            (typeof x === "object" && x instanceof RegExp);
-    }
-
-    function isObject(x) {
-        return (x !== null) && (typeof x === "object");
-    }
-
-    function isFunction(x) {
-        return typeof x === "function";
-    }
-
-    function isArrayLike(x) {
-        return isObject(x) && ("length" in x);
-    }
-
-    function matchAtom(act, exp) {
-        if ((typeof exp) === "number" && isNaN(exp)) {
-            if ((typeof act) !== "number" || !isNaN(act))
-                throw new MatchError("expected NaN, got: " + quote(act));
-            return true;
+        return true;
+      case "boolean":
+      case "number":
+        if (exp !== act) {
+          throw new MatchError("expected " + exp + ", got " + quote(act));
         }
-
-        if (exp === null) {
-            if (act !== null)
-                throw new MatchError("expected null, got: " + quote(act));
-            return true;
-        }
-
-        if (exp instanceof RegExp) {
-            if (!(act instanceof RegExp) || exp.source !== act.source)
-                throw new MatchError("expected " + quote(exp) + ", got: " + quote(act));
-            return true;
-        }
-
-        switch (typeof exp) {
-        case "string":
-            if (act !== exp)
-                throw new MatchError("expected " + quote(exp) + ", got " + quote(act));
-            return true;
-        case "boolean":
-        case "number":
-            if (exp !== act)
-                throw new MatchError("expected " + exp + ", got " + quote(act));
-            return true;
-        }
-
-        throw new Error("bad pattern: " + exp.toSource());
-    }
-
-    function matchObject(act, exp) {
-        if (!isObject(act))
-            throw new MatchError("expected object, got " + quote(act));
-
-        for (var key in exp) {
-            if (!(key in act))
-                throw new MatchError("expected property " + quote(key) + " not found in " + quote(act));
-            match(act[key], exp[key]);
-        }
-
         return true;
     }
 
-    function matchFunction(act, exp) {
-        if (!isFunction(act))
-            throw new MatchError("expected function, got " + quote(act));
+    throw new Error("bad pattern: " + exp.toSource());
+  }
 
-        if (act !== exp)
-            throw new MatchError("expected function: " + exp +
-                                 "\nbut got different function: " + act);
+  function matchObject(act, exp) {
+    if (!isObject(act)) {
+      throw new MatchError("expected object, got " + quote(act));
     }
 
-    function matchArray(act, exp) {
-        if (!isObject(act) || !("length" in act))
-            throw new MatchError("expected array-like object, got " + quote(act));
+    for (let key in exp) {
+      if (!(key in act)) {
+        throw new MatchError("expected property " + quote(key)
+          + " not found in " + quote(act));
+      }
+      match(act[key], exp[key]);
+    }
 
-        var length = exp.length;
-        if (act.length !== exp.length)
-            throw new MatchError("expected array-like object of length " + length + ", got " + quote(act));
+    return true;
+  }
 
-        for (var i = 0; i < length; i++) {
-            if (i in exp) {
-                if (!(i in act))
-                    throw new MatchError("expected array property " + i + " not found in " + quote(act));
-                match(act[i], exp[i]);
-            }
+  function matchFunction(act, exp) {
+    if (!isFunction(act)) {
+      throw new MatchError("expected function, got " + quote(act));
+    }
+
+    if (act !== exp) {
+      throw new MatchError("expected function: " + exp +
+                             "\nbut got different function: " + act);
+    }
+  }
+
+  function matchArray(act, exp) {
+    if (!isObject(act) || !("length" in act)) {
+      throw new MatchError("expected array-like object, got " + quote(act));
+    }
+
+    let length = exp.length;
+    if (act.length !== exp.length) {
+      throw new MatchError("expected array-like object of length "
+        + length + ", got " + quote(act));
+    }
+
+    for (let i = 0; i < length; i++) {
+      if (i in exp) {
+        if (!(i in act)) {
+          throw new MatchError("expected array property " + i + " not found in "
+            + quote(act));
         }
-
-        return true;
+        match(act[i], exp[i]);
+      }
     }
 
-    function match(act, exp) {
-        if (exp === Pattern.ANY)
-            return true;
+    return true;
+  }
 
-        if (exp instanceof Pattern)
-            return exp.match(act);
-
-        if (isAtom(exp))
-            return matchAtom(act, exp);
-
-        if (isArrayLike(exp))
-            return matchArray(act, exp);
-
-        if (isFunction(exp))
-            return matchFunction(act, exp);
-
-        return matchObject(act, exp);
+  function match(act, exp) {
+    if (exp === Pattern.ANY) {
+      return true;
     }
 
-    return { Pattern: Pattern,
-             MatchError: MatchError };
+    if (exp instanceof Pattern) {
+      return exp.match(act);
+    }
 
+    if (isAtom(exp)) {
+      return matchAtom(act, exp);
+    }
+
+    if (isArrayLike(exp)) {
+      return matchArray(act, exp);
+    }
+
+    if (isFunction(exp)) {
+      return matchFunction(act, exp);
+    }
+
+    return matchObject(act, exp);
+  }
+
+  return { Pattern, MatchError };
 })();
diff --git a/devtools/shared/heapsnapshot/tests/unit/dominator-tree-worker.js b/devtools/shared/heapsnapshot/tests/unit/dominator-tree-worker.js
index 1f49ca8417a5..f0fdc37438cc 100644
--- a/devtools/shared/heapsnapshot/tests/unit/dominator-tree-worker.js
+++ b/devtools/shared/heapsnapshot/tests/unit/dominator-tree-worker.js
@@ -1,6 +1,8 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
+"use strict";
+
 console.log("Initializing worker.");
 
 self.onmessage = e => {
@@ -16,12 +18,12 @@ self.onmessage = e => {
     let threw = false;
     try {
       new DominatorTree();
-    } catch (e) {
+    } catch (excp) {
       threw = true;
     }
     ok(threw, "Constructor shouldn't be usable");
-  } catch (e) {
-    ok(false, "Unexpected error inside worker:\n" + e.toString() + "\n" + e.stack);
+  } catch (ex) {
+    ok(false, "Unexpected error inside worker:\n" + ex.toString() + "\n" + ex.stack);
   } finally {
     done();
   }
diff --git a/devtools/shared/heapsnapshot/tests/unit/head_heapsnapshot.js b/devtools/shared/heapsnapshot/tests/unit/head_heapsnapshot.js
index 3171c8a6f411..bbbbff7eac4d 100644
--- a/devtools/shared/heapsnapshot/tests/unit/head_heapsnapshot.js
+++ b/devtools/shared/heapsnapshot/tests/unit/head_heapsnapshot.js
@@ -2,6 +2,12 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
+/* exported Cr, CC, Match, Census, Task, DevToolsUtils, HeapAnalysesClient,
+  assertThrows, getFilePath, saveHeapSnapshotAndTakeCensus,
+  saveHeapSnapshotAndComputeDominatorTree, compareCensusViewData, assertDiff,
+  assertLabelAndShallowSize, makeTestDominatorTreeNode,
+  assertDominatorTreeNodeInsertion, assertDeduplicatedPaths,
+  assertCountToBucketBreakdown, pathEntry */
 
 var Cc = Components.classes;
 var Ci = Components.interfaces;
@@ -14,7 +20,6 @@ const { Match } = Cu.import("resource://test/Match.jsm", {});
 const { Census } = Cu.import("resource://test/Census.jsm", {});
 const { addDebuggerToGlobal } =
   Cu.import("resource://gre/modules/jsdebugger.jsm", {});
-const { Task } = require("devtools/shared/task");
 
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const flags = require("devtools/shared/flags");
@@ -27,7 +32,6 @@ const DominatorTreeNode = require("devtools/shared/heapsnapshot/DominatorTreeNod
 const { deduplicatePaths } = require("devtools/shared/heapsnapshot/shortest-paths");
 const { LabelAndShallowSizeVisitor } = DominatorTreeNode;
 
-
 // Always log packets when running tests. runxpcshelltests.py will throw
 // the output away anyway, unless you give it the --verbose flag.
 if (Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_DEFAULT) {
@@ -75,19 +79,24 @@ function newGlobal() {
   return global;
 }
 
-function assertThrowsValue(f, val, msg) {
-  var fullmsg;
+function assertThrows(f, val, msg) {
+  let fullmsg;
   try {
     f();
   } catch (exc) {
-    if ((exc === val) === (val === val) && (val !== 0 || 1 / exc === 1 / val))
+    if ((exc === val) && (val !== 0 || 1 / exc === 1 / val)) {
       return;
+    } else if (exc instanceof Error && exc.message === val) {
+      return;
+    }
     fullmsg = "Assertion failed: expected exception " + val + ", got " + exc;
   }
-  if (fullmsg === undefined)
+  if (fullmsg === undefined) {
     fullmsg = "Assertion failed: expected exception " + val + ", no exception thrown";
-  if (msg !== undefined)
+  }
+  if (msg !== undefined) {
     fullmsg += " - " + msg;
+  }
   throw new Error(fullmsg);
 }
 
@@ -95,9 +104,8 @@ function assertThrowsValue(f, val, msg) {
  * Returns the full path of the file with the specified name in a
  * platform-independent and URL-like form.
  */
-function getFilePath(aName, aAllowMissing = false, aUsePlatformPathSeparator = false)
-{
-  let file = do_get_file(aName, aAllowMissing);
+function getFilePath(name, allowMissing = false, usePlatformPathSeparator = false) {
+  let file = do_get_file(name, allowMissing);
   let path = Services.io.newFileURI(file).spec;
   let filePrePath = "file://";
   if ("nsILocalFileWin" in Ci &&
@@ -107,7 +115,7 @@ function getFilePath(aName, aAllowMissing = false, aUsePlatformPathSeparator = f
 
   path = path.slice(filePrePath.length);
 
-  if (aUsePlatformPathSeparator && path.match(/^\w:/)) {
+  if (sePlatformPathSeparator && path.match(/^\w:/)) {
     path = path.replace(/\//g, "\\");
   }
 
@@ -152,7 +160,8 @@ function saveHeapSnapshotAndTakeCensus(dbg = null, censusOptions = undefined) {
   const filePath = saveNewHeapSnapshot(snapshotOptions);
   const snapshot = readHeapSnapshot(filePath);
 
-  equal(typeof snapshot.takeCensus, "function", "snapshot should have a takeCensus method");
+  equal(typeof snapshot.takeCensus, "function",
+    "snapshot should have a takeCensus method");
 
   return snapshot.takeCensus(censusOptions);
 }
@@ -190,9 +199,8 @@ function isSavedFrame(obj) {
 function savedFrameReplacer(key, val) {
   if (isSavedFrame(val)) {
     return ``;
-  } else {
-    return val;
   }
+  return val;
 }
 
 /**
@@ -244,7 +252,7 @@ function assertStructurallyEquivalent(actual, expected, path = "root") {
 
       for (let key of actual.keys()) {
         ok(expectedKeys.has(key),
-           `${path}: every key in actual should exist in expected: ${String(key).slice(0, 10)}`);
+          `${path}: every key in actual is expected: ${String(key).slice(0, 10)}`);
         expectedKeys.delete(key);
 
         assertStructurallyEquivalent(actual.get(key), expected.get(key),
@@ -252,7 +260,8 @@ function assertStructurallyEquivalent(actual, expected, path = "root") {
       }
 
       equal(expectedKeys.size, 0,
-            `${path}: every key in expected should also exist in actual, did not see ${[...expectedKeys]}`);
+        `${path}: every key in expected should also exist in actual,\
+        did not see ${[...expectedKeys]}`);
     } else if (actualProtoString === "[object Set]") {
       const expectedItems = new Set([...expected]);
 
@@ -263,7 +272,8 @@ function assertStructurallyEquivalent(actual, expected, path = "root") {
       }
 
       equal(expectedItems.size, 0,
-            `${path}: every set item in expected should also exist in actual, did not see ${[...expectedItems]}`);
+        `${path}: every set item in expected should also exist in actual,\
+        did not see ${[...expectedItems]}`);
     } else {
       const expectedKeys = new Set(Object.keys(expected));
 
@@ -276,7 +286,8 @@ function assertStructurallyEquivalent(actual, expected, path = "root") {
       }
 
       equal(expectedKeys.size, 0,
-            `${path}: every key in expected should also exist in actual, did not see ${[...expectedKeys]}`);
+        `${path}: every key in expected should also exist in actual,\
+        did not see ${[...expectedKeys]}`);
     }
   } else {
     equal(actual, expected, `${path}: primitives should be equal`);
@@ -321,7 +332,8 @@ function assertDiff(breakdown, first, second, expected) {
  * @param {Number} expectedShallowSize
  * @param {Object} expectedLabel
  */
-function assertLabelAndShallowSize(breakdown, givenDescription, expectedShallowSize, expectedLabel) {
+function assertLabelAndShallowSize(breakdown, givenDescription,
+  expectedShallowSize, expectedLabel) {
   dumpn("Computing label and shallow size from node description:");
   dumpn("Breakdown: " + JSON.stringify(breakdown, null, 4));
   dumpn("Given description: " + JSON.stringify(givenDescription, null, 4));
@@ -364,7 +376,7 @@ function makeTestDominatorTreeNode(opts, children) {
   }, opts);
 
   if (children && children.length) {
-    children.map(c => c.parentId = node.nodeId);
+    children.map(c => (c.parentId = node.nodeId));
   }
 
   return node;
@@ -375,7 +387,8 @@ function makeTestDominatorTreeNode(opts, children) {
  * `path` from the root to the node the `newChildren` should be inserted
  * beneath. Assert that the resulting tree matches `expected`.
  */
-function assertDominatorTreeNodeInsertion(tree, path, newChildren, moreChildrenAvailable, expected) {
+function assertDominatorTreeNodeInsertion(tree, path, newChildren,
+  moreChildrenAvailable, expected) {
   dumpn("Inserting new children into a dominator tree:");
   dumpn("Dominator tree: " + JSON.stringify(tree, null, 2));
   dumpn("Path: " + JSON.stringify(path, null, 2));
@@ -425,7 +438,8 @@ function assertDeduplicatedPaths({ target, paths, expectedNodes, expectedEdges }
       }
     }
     equal(count, 1,
-          "should have exactly one matching edge for the expected edge = " + JSON.stringify(edge));
+      "should have exactly one matching edge for the expected edge = "
+      + JSON.stringify(edge));
   }
 }
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/heap-snapshot-worker.js b/devtools/shared/heapsnapshot/tests/unit/heap-snapshot-worker.js
index 10ee70cec62b..ba23185970ee 100644
--- a/devtools/shared/heapsnapshot/tests/unit/heap-snapshot-worker.js
+++ b/devtools/shared/heapsnapshot/tests/unit/heap-snapshot-worker.js
@@ -1,9 +1,11 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
+"use strict";
+
 console.log("Initializing worker.");
 
-self.onmessage = e => {
+self.onmessage = ex => {
   console.log("Starting test.");
   try {
     ok(typeof ChromeUtils === "undefined",
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_01.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_01.js
index 845a0d263bb6..a3db538b2fc8 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can generate label structures from node description reports.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_02.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_02.js
index e1f32de58b3e..8f502a7c9a25 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can generate label structures from node description reports.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_03.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_03.js
index ad35dcec1700..33e597021ebf 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can generate label structures from node description reports.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_04.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_04.js
index 566ad0dab136..5f1b1b45b558 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_04.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_LabelAndShallowSize_04.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can generate label structures from node description reports.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_attachShortestPaths_01.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_attachShortestPaths_01.js
index 24e8e2eb57e5..310e2b3790ea 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_attachShortestPaths_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_attachShortestPaths_01.js
@@ -69,7 +69,8 @@ const expected = [
     }
   }),
 
-  makeTestDominatorTreeNode({ nodeId: 3000,
+  makeTestDominatorTreeNode({
+    nodeId: 3000,
     shortestPaths: {
       nodes: [
         { id: 3000, label: ["SomeType-3000"] },
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_getNodeByIdAlongPath_01.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_getNodeByIdAlongPath_01.js
index de2907809d72..9942744bce53 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_getNodeByIdAlongPath_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_getNodeByIdAlongPath_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can find the node with the given id along the specified path.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_01.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_01.js
index 979232ff498a..c1f00a90476f 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can insert new children into an existing DominatorTreeNode tree.
 
@@ -108,5 +109,6 @@ const expected = {
 };
 
 function run_test() {
-  assertDominatorTreeNodeInsertion(tree, path, newChildren, moreChildrenAvailable, expected);
+  assertDominatorTreeNodeInsertion(tree, path, newChildren,
+    moreChildrenAvailable, expected);
 }
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_02.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_02.js
index 9a8d11d0b534..098ecebd4763 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test attempting to insert new children into an existing DominatorTreeNode
 // tree with a bad path.
@@ -26,5 +27,6 @@ const moreChildrenAvailable = false;
 const expected = tree;
 
 function run_test() {
-  assertDominatorTreeNodeInsertion(tree, path, newChildren, moreChildrenAvailable, expected);
+  assertDominatorTreeNodeInsertion(tree, path, newChildren,
+    moreChildrenAvailable, expected);
 }
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_03.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_03.js
index f8cb5eec3895..eaad66231504 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_insert_03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test inserting new children into an existing DominatorTreeNode at the root.
 
@@ -113,5 +114,6 @@ const expected = {
 };
 
 function run_test() {
-  assertDominatorTreeNodeInsertion(tree, path, newChildren, moreChildrenAvailable, expected);
+  assertDominatorTreeNodeInsertion(tree, path, newChildren,
+    moreChildrenAvailable, expected);
 }
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_partialTraversal_01.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_partialTraversal_01.js
index 78ec47b646f5..c0fe9af2ea72 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_partialTraversal_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTreeNode_partialTraversal_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we correctly set `moreChildrenAvailable` when doing a partial
 // traversal of a dominator tree to create the initial incrementally loaded
@@ -154,8 +155,10 @@ function run_test() {
   const actual = DominatorTreeNode.partialTraversal(mockDominatorTree,
                                                     mockSnapshot,
                                                     breakdown,
-                                                    /* maxDepth = */ 4,
-                                                    /* siblings = */ 2);
+                                                    // maxDepth
+                                                    4,
+                                                    // siblings
+                                                    2);
 
   dumpn("Expected = " + JSON.stringify(expected, null, 2));
   dumpn("Actual = " + JSON.stringify(actual, null, 2));
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_01.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_01.js
index e8145f658acd..605d037fa924 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Sanity test that we can compute dominator trees.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_02.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_02.js
index ab49379605d2..ae4d40713494 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can compute dominator trees from a snapshot in a worker.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_03.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_03.js
index 0a14ce53dae0..40ff8571c194 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can get the root of dominator trees.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_04.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_04.js
index e5aef3fec1a1..4cd70859a4da 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_04.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_04.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can get the retained sizes of dominator trees.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_05.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_05.js
index c07cee994446..63d80ef97503 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_05.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_05.js
@@ -1,11 +1,12 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can get the set of immediately dominated nodes for any given
 // node and that this forms a tree.
 
 function run_test() {
-  var dominatorTree = saveHeapSnapshotAndComputeDominatorTree();
+  let dominatorTree = saveHeapSnapshotAndComputeDominatorTree();
   equal(typeof dominatorTree.getImmediatelyDominated, "function",
         "getImmediatelyDominated should be a function");
 
@@ -16,33 +17,33 @@ function run_test() {
   // every one. This test would constantly time out and assertion messages would
   // overflow the log size.
 
-  var root = dominatorTree.root;
+  let root = dominatorTree.root;
   equal(dominatorTree.getImmediateDominator(root), null,
         "The root should not have a parent");
 
-  var seen = new Set();
-  var stack = [root];
+  let seen = new Set();
+  let stack = [root];
   while (stack.length > 0) {
-    var top = stack.pop();
+    let top = stack.pop();
 
     if (seen.has(top)) {
-      ok(false,
-         "This is a tree, not a graph: we shouldn't have multiple edges to the same node");
+      ok(false, "This is a tree, not a graph: we shouldn't have "
+        + "multiple edges to the same node");
     }
     seen.add(top);
     if (seen.size % 1000 === 0) {
       dumpn("Progress update: seen size = " + seen.size);
     }
 
-    var newNodes = dominatorTree.getImmediatelyDominated(top);
+    let newNodes = dominatorTree.getImmediatelyDominated(top);
     if (Object.prototype.toString.call(newNodes) !== "[object Array]") {
       ok(false, "getImmediatelyDominated should return an array for known node ids");
     }
 
-    var topSize = dominatorTree.getRetainedSize(top);
+    let topSize = dominatorTree.getRetainedSize(top);
 
-    var lastSize = Infinity;
-    for (var i = 0; i < newNodes.length; i++) {
+    let lastSize = Infinity;
+    for (let i = 0; i < newNodes.length; i++) {
       if (typeof newNodes[i] !== "number") {
         ok(false, "Every dominated id should be a number");
       }
@@ -51,10 +52,11 @@ function run_test() {
         ok(false, "child's parent should be the expected parent");
       }
 
-      var thisSize = dominatorTree.getRetainedSize(newNodes[i]);
+      let thisSize = dominatorTree.getRetainedSize(newNodes[i]);
 
       if (thisSize >= topSize) {
-        ok(false, "the size of children in the dominator tree should always be less than that of their parent");
+        ok(false, "the size of children in the dominator tree should"
+          + " always be less than that of their parent");
       }
 
       if (thisSize > lastSize) {
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_06.js b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_06.js
index 680478623f2e..8dd8de59d6d0 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_06.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_DominatorTree_06.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the retained size of a node is the sum of its children retained
 // sizes plus its shallow size.
@@ -14,31 +15,31 @@ function fastAssert(cond, msg) {
   }
 }
 
-var COUNT = { by: "count", count: false, bytes: true };
+let COUNT = { by: "count", count: false, bytes: true };
 
 function run_test() {
-  var path = saveNewHeapSnapshot();
-  var snapshot = ChromeUtils.readHeapSnapshot(path);
-  var dominatorTree = snapshot.computeDominatorTree();
+  let path = saveNewHeapSnapshot();
+  let snapshot = ChromeUtils.readHeapSnapshot(path);
+  let dominatorTree = snapshot.computeDominatorTree();
 
   // Do a traversal of the dominator tree and assert the relationship between
   // retained size, shallow size, and children's retained sizes.
 
-  var root = dominatorTree.root;
-  var stack = [root];
+  let root = dominatorTree.root;
+  let stack = [root];
   while (stack.length > 0) {
-    var top = stack.pop();
+    let top = stack.pop();
 
-    var children = dominatorTree.getImmediatelyDominated(top);
+    let children = dominatorTree.getImmediatelyDominated(top);
 
-    var topRetainedSize = dominatorTree.getRetainedSize(top);
-    var topShallowSize = snapshot.describeNode(COUNT, top).bytes;
+    let topRetainedSize = dominatorTree.getRetainedSize(top);
+    let topShallowSize = snapshot.describeNode(COUNT, top).bytes;
     fastAssert(topShallowSize <= topRetainedSize,
                "The shallow size should be less than or equal to the " +
                "retained size");
 
-    var sumOfChildrensRetainedSizes = 0;
-    for (var i = 0; i < children.length; i++) {
+    let sumOfChildrensRetainedSizes = 0;
+    for (let i = 0; i < children.length; i++) {
       sumOfChildrensRetainedSizes += dominatorTree.getRetainedSize(children[i]);
       stack.push(children[i]);
     }
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_01.js
index 0114e0b696f0..e04b600ba04f 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test the HeapAnalyses{Client,Worker} "computeDominatorTree" request.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_02.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_02.js
index 6e3f5b257e2e..dc4f0f644046 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_computeDominatorTree_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test the HeapAnalyses{Client,Worker} "computeDominatorTree" request with bad
 // file paths.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_01.js
index 7708de93c295..787434e7ded5 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can delete heap snapshots.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_02.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_02.js
index 3e25ddac4726..4c85c68a7e15 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test deleteHeapSnapshot is a noop if the provided path matches no snapshot
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_03.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_03.js
index e648c9407879..6ea499d47bd8 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test other dominatorTrees can still be retrieved after deleting a snapshot
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getCensusIndividuals_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getCensusIndividuals_01.js
index b63ad4230745..e54b40ed1ce2 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getCensusIndividuals_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getCensusIndividuals_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can get census individuals.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getCreationTime_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getCreationTime_01.js
index 5df79de7ac3a..a0f5a1e1086c 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getCreationTime_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getCreationTime_01.js
@@ -1,12 +1,15 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can get a HeapSnapshot's
 // creation time.
 
 function waitForThirtyMilliseconds() {
   const start = Date.now();
-  while (Date.now() - start < 30) ;
+  while (Date.now() - start < 30) {
+    // do nothing
+  }
 }
 
 function run_test() {
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getDominatorTree_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getDominatorTree_01.js
index cedea5375418..3b3f77765b27 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getDominatorTree_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getDominatorTree_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test the HeapAnalyses{Client,Worker} "getDominatorTree" request.
 
@@ -47,7 +48,8 @@ add_task(function* () {
           "each node should have a retained size");
 
     ok(node.children === undefined || Array.isArray(node.children),
-       "each node either has a list of children, or undefined meaning no children loaded");
+       "each node either has a list of children, "
+       + "or undefined meaning no children loaded");
     equal(typeof node.moreChildrenAvailable, "boolean",
           "each node should indicate if there are more children available or not");
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getDominatorTree_02.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getDominatorTree_02.js
index fd29beecee85..bc53634833fd 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getDominatorTree_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getDominatorTree_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test the HeapAnalyses{Client,Worker} "getDominatorTree" request with bad
 // dominator tree ids.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getImmediatelyDominated_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getImmediatelyDominated_01.js
index caf1c2056922..34d5c96acca7 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getImmediatelyDominated_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_getImmediatelyDominated_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test the HeapAnalyses{Client,Worker} "getImmediatelyDominated" request.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_readHeapSnapshot_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_readHeapSnapshot_01.js
index 0d0d58bef667..d86967ae414a 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_readHeapSnapshot_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_readHeapSnapshot_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can read heap snapshots.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_01.js
index 6f22cbad3998..09442a319f26 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can take diffs between censuses.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_02.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_02.js
index f1ba9ce84922..4f91ff8ede9d 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can take diffs between censuses as
 // inverted trees.
@@ -43,10 +44,11 @@ add_task(function* () {
                                                 secondSnapshotFilePath,
                                                 { breakdown: BREAKDOWN });
 
-  const { delta: deltaTreeNode } = yield client.takeCensusDiff(firstSnapshotFilePath,
-                                                               secondSnapshotFilePath,
-                                                               { breakdown: BREAKDOWN },
-                                                               { asInvertedTreeNode: true });
+  const { delta: deltaTreeNode }
+    = yield client.takeCensusDiff(firstSnapshotFilePath,
+                                 secondSnapshotFilePath,
+                                 { breakdown: BREAKDOWN },
+                                 { asInvertedTreeNode: true });
 
   // Have to manually set these because symbol properties aren't structured
   // cloned.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_01.js
index e26981db4c4f..59aa4b379c96 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can take censuses.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_02.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_02.js
index 34494af704b3..65f2db5bca98 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can take censuses with breakdown
 // options.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_03.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_03.js
index 486e250b5db9..ee79448af159 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} bubbles errors properly when things
 // go wrong.
@@ -27,7 +28,8 @@ add_task(function* () {
   } catch (e) {
     failed = true;
   }
-  ok(failed, "should not be able to read a file that is not a heap snapshot as a heap snapshot");
+  ok(failed, "should not be able to read a file "
+    + "that is not a heap snapshot as a heap snapshot");
 
   const snapshotFilePath = saveNewHeapSnapshot();
   yield client.readHeapSnapshot(snapshotFilePath);
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_04.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_04.js
index 769a2d99d369..a5e50d58a523 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_04.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_04.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can send SavedFrame stacks from
 // by-allocation-stack reports from the worker.
@@ -20,7 +21,7 @@ add_task(function* test() {
          function f() { this.log.push(allocationMarker()); } // 3
          function g() { this.log.push(allocationMarker()); } // 4
          function h() { this.log.push(allocationMarker()); } // 5
-         `);                                                 // 6
+         `);
 
   // Create one allocationMarker with tracking turned off,
   // so it will have no associated stack.
@@ -49,20 +50,26 @@ add_task(function* test() {
   // Run a census broken down by class name -> allocation stack so we can grab
   // only the AllocationMarker objects we have complete control over.
 
-  const { report } = yield client.takeCensus(snapshotFilePath, {
-    breakdown: { by: "objectClass",
-                 then: { by: "allocationStack",
-                         then: { by: "count",
-                                 bytes: true,
-                                 count: true
-                               },
-                         noStack: { by: "count",
-                                    bytes: true,
-                                    count: true
-                                  }
-                       }
-               }
-  });
+  const { report } = yield client.takeCensus(
+    snapshotFilePath,
+    {
+      breakdown: {
+        by: "objectClass",
+        then: {
+          by: "allocationStack",
+          then: {
+            by: "count",
+            bytes: true,
+            count: true
+          },
+          noStack: {
+            by: "count",
+            bytes: true,
+            count: true
+          }
+        }
+      }
+    });
 
   // Test the generated report.
 
@@ -72,7 +79,7 @@ add_task(function* test() {
   ok(map, "Should get AllocationMarkers in the report.");
   // From a module with a different global, and therefore a different Map
   // constructor, so we can't use instanceof.
-  equal(map.__proto__.constructor.name, "Map");
+  equal(Object.getPrototypeOf(map).constructor.name, "Map");
 
   equal(map.size, 4, "Should have 4 allocation stacks (including the lack of a stack)");
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_05.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_05.js
index 7e16d9f00f39..8007e6f95c1b 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_05.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_05.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can take censuses and return
 // a CensusTreeNode.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_06.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_06.js
index 7795a97007da..d90cf72c5505 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_06.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_06.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can take censuses by
 // "allocationStack" and return a CensusTreeNode.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_07.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_07.js
index 986b3aaa808a..edefa973314c 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_07.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_07.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that the HeapAnalyses{Client,Worker} can take censuses and return
 // an inverted CensusTreeNode.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_computeShortestPaths_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_computeShortestPaths_01.js
index 2ec577bd00ea..ac23224c7aa5 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_computeShortestPaths_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_computeShortestPaths_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Sanity test that we can compute shortest paths.
 //
@@ -21,7 +22,8 @@ function run_test() {
 
   const targetSet = new Set(dominatedByRoot);
 
-  const shortestPaths = snapshot.computeShortestPaths(dominatorTree.root, dominatedByRoot, 2);
+  const shortestPaths
+    = snapshot.computeShortestPaths(dominatorTree.root, dominatedByRoot, 2);
   ok(shortestPaths);
   ok(shortestPaths instanceof Map);
   ok(shortestPaths.size === targetSet.size);
@@ -38,21 +40,21 @@ function run_test() {
 
     dumpn("---------------------");
     dumpn("Shortest paths for 0x" + target.toString(16) + ":");
-    for (let path of paths) {
+    for (let pth of paths) {
       dumpn("    path =");
-      for (let part of path) {
+      for (let part of pth) {
         dumpn("        predecessor: 0x" + part.predecessor.toString(16) +
               "; edge: " + part.edge);
       }
     }
     dumpn("---------------------");
 
-    for (let path of paths) {
-      ok(path.length > 0, "Cannot have zero length paths");
-      ok(path[0].predecessor === dominatorTree.root,
+    for (let path2 of paths) {
+      ok(path2.length > 0, "Cannot have zero length paths");
+      ok(path2[0].predecessor === dominatorTree.root,
          "The first predecessor is always our start node");
 
-      for (let part of path) {
+      for (let part of path2) {
         ok(part.predecessor, "Each part of a path has a predecessor");
         ok(!!snapshot.describeNode({ by: "count", count: true, bytes: true},
                                    part.predecessor),
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_computeShortestPaths_02.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_computeShortestPaths_02.js
index 04fe58733b22..a1511de0fd23 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_computeShortestPaths_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_computeShortestPaths_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test computing shortest paths with invalid arguments.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_creationTime_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_creationTime_01.js
index 0d08fea16cdc..075e7f18ef70 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_creationTime_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_creationTime_01.js
@@ -1,11 +1,14 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // HeapSnapshot.prototype.creationTime returns the expected time.
 
 function waitForThirtyMilliseconds() {
   const start = Date.now();
-  while (Date.now() - start < 30) ;
+  while (Date.now() - start < 30) {
+    // do nothing
+  }
 }
 
 function run_test() {
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_deepStack_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_deepStack_01.js
index 9eb11d9afe8e..544f00d30502 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_deepStack_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_deepStack_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can save a core dump with very deep allocation stacks and read
 // it back into a HeapSnapshot.
@@ -20,8 +21,9 @@ function run_test() {
   debuggee.eval("this.objects = []");
   debuggee.eval(
     (function recursiveAllocate(n) {
-      if (n <= 0)
+      if (n <= 0) {
         return;
+      }
 
       // Make sure to recurse before pushing the object so that when TCO is
       // implemented sometime in the future, it doesn't invalidate this test.
@@ -46,7 +48,7 @@ function run_test() {
     breakdown: { by: "allocationStack",
                  then: { by: "count", bytes: true, count: true },
                  noStack: { by: "count", bytes: true, count: true }
-               }
+    }
   });
 
   // Keep this synchronized with `HeapSnapshot::MAX_STACK_DEPTH`!
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_describeNode_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_describeNode_01.js
index d79cb5a7b4e9..72aa1eb4b5b4 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_describeNode_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_describeNode_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can describe nodes with a breakdown.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_01.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_01.js
index f3b3090b0825..ff6565d3d96e 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_01.js
@@ -1,29 +1,31 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // HeapSnapshot.prototype.takeCensus returns a value of an appropriate
 // shape. Ported from js/src/jit-tests/debug/Memory-takeCensus-01.js
 
 function run_test() {
-  var dbg = new Debugger;
+  let dbg = new Debugger();
 
   function checkProperties(census) {
     equal(typeof census, "object");
-    for (prop of Object.getOwnPropertyNames(census)) {
-      var desc = Object.getOwnPropertyDescriptor(census, prop);
+    for (let prop of Object.getOwnPropertyNames(census)) {
+      let desc = Object.getOwnPropertyDescriptor(census, prop);
       equal(desc.enumerable, true);
       equal(desc.configurable, true);
       equal(desc.writable, true);
-      if (typeof desc.value === "object")
+      if (typeof desc.value === "object") {
         checkProperties(desc.value);
-      else
+      } else {
         equal(typeof desc.value, "number");
+      }
     }
   }
 
   checkProperties(saveHeapSnapshotAndTakeCensus(dbg));
 
-  var g = newGlobal();
+  let g = newGlobal();
   dbg.addDebuggee(g);
   checkProperties(saveHeapSnapshotAndTakeCensus(dbg));
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_02.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_02.js
index 680ac9b58b8f..4887d7bdf5ec 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // HeapSnapshot.prototype.takeCensus behaves plausibly as we allocate objects.
 //
@@ -15,12 +16,12 @@
 
 function run_test() {
   // A Debugger with no debuggees had better not find anything.
-  var dbg = new Debugger;
-  var census0 = saveHeapSnapshotAndTakeCensus(dbg);
+  let dbg = new Debugger();
+  let census0 = saveHeapSnapshotAndTakeCensus(dbg);
   Census.walkCensus(census0, "census0", Census.assertAllZeros);
 
   function newGlobalWithDefs() {
-    var g = newGlobal();
+    let g = newGlobal();
     g.eval(`
            function times(n, fn) {
              var a=[];
@@ -34,7 +35,7 @@ function run_test() {
 
   // Allocate a large number of various types of objects, and check that census
   // finds them.
-  var g = newGlobalWithDefs();
+  let g = newGlobalWithDefs();
   dbg.addDebuggee(g);
 
   g.eval("var objs = times(100, () => ({}));");
@@ -42,16 +43,16 @@ function run_test() {
   g.eval("var ars  = times(400, () => []);");
   g.eval("var fns  = times(800, () => () => {});");
 
-  var census1 = dbg.memory.takeCensus(dbg);
+  let census1 = dbg.memory.takeCensus(dbg);
   Census.walkCensus(census1, "census1",
-                    Census.assertAllNotLessThan(
-                      { "objects":
-                        { "Object":   { count: 100 },
-                          "RegExp":   { count: 200 },
-                          "Array":    { count: 400 },
-                          "Function": { count: 800 }
-                        }
-                      }));
+                    Census.assertAllNotLessThan({
+                      "objects": {
+                        "Object": { count: 100 },
+                        "RegExp": { count: 200 },
+                        "Array": { count: 400 },
+                        "Function": { count: 800 }
+                      }
+                    }));
 
   do_test_finished();
 }
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_03.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_03.js
index 25f2c379121f..df215c9fb067 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // HeapSnapshot.prototype.takeCensus behaves plausibly as we add and remove
 // debuggees.
@@ -7,27 +8,27 @@
 // Ported from js/src/jit-test/tests/debug/Memory-takeCensus-03.js
 
 function run_test() {
-  var dbg = new Debugger;
+  let dbg = new Debugger();
 
-  var census0 = saveHeapSnapshotAndTakeCensus(dbg);
+  let census0 = saveHeapSnapshotAndTakeCensus(dbg);
   Census.walkCensus(census0, "census0", Census.assertAllZeros);
 
-  var g1 = newGlobal();
+  let g1 = newGlobal();
   dbg.addDebuggee(g1);
-  var census1 = saveHeapSnapshotAndTakeCensus(dbg);
+  let census1 = saveHeapSnapshotAndTakeCensus(dbg);
   Census.walkCensus(census1, "census1", Census.assertAllNotLessThan(census0));
 
-  var g2 = newGlobal();
+  let g2 = newGlobal();
   dbg.addDebuggee(g2);
-  var census2 = saveHeapSnapshotAndTakeCensus(dbg);
+  let census2 = saveHeapSnapshotAndTakeCensus(dbg);
   Census.walkCensus(census2, "census2", Census.assertAllNotLessThan(census1));
 
   dbg.removeDebuggee(g2);
-  var census3 = saveHeapSnapshotAndTakeCensus(dbg);
+  let census3 = saveHeapSnapshotAndTakeCensus(dbg);
   Census.walkCensus(census3, "census3", Census.assertAllEqual(census1));
 
   dbg.removeDebuggee(g1);
-  var census4 = saveHeapSnapshotAndTakeCensus(dbg);
+  let census4 = saveHeapSnapshotAndTakeCensus(dbg);
   Census.walkCensus(census4, "census4", Census.assertAllEqual(census0));
 
   do_test_finished();
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_04.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_04.js
index 799844cde002..67b7385e554b 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_04.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_04.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that HeapSnapshot.prototype.takeCensus finds GC roots that are on the
 // stack.
@@ -7,8 +8,8 @@
 // Ported from js/src/jit-test/tests/debug/Memory-takeCensus-04.js
 
 function run_test() {
-  var g = newGlobal();
-  var dbg = new Debugger(g);
+  let g = newGlobal();
+  let dbg = new Debugger(g);
 
   g.eval(`
 function withAllocationMarkerOnStack(f) {
@@ -22,7 +23,7 @@ function withAllocationMarkerOnStack(f) {
   equal("AllocationMarker" in saveHeapSnapshotAndTakeCensus(dbg).objects, false,
         "There shouldn't exist any allocation markers in the census.");
 
-  var allocationMarkerCount;
+  let allocationMarkerCount;
   g.withAllocationMarkerOnStack(() => {
     const census = saveHeapSnapshotAndTakeCensus(dbg);
     allocationMarkerCount = census.objects.AllocationMarker.count;
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_05.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_05.js
index da6067624adf..78a3c163ef51 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_05.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_05.js
@@ -6,9 +6,10 @@
 //
 // Ported from js/src/jit-test/tests/debug/Memory-takeCensus-05.js
 
+/* eslint-disable strict */
 function run_test() {
-  var g = newGlobal();
-  var dbg = new Debugger(g);
+  let g = newGlobal();
+  let dbg = new Debugger(g);
 
   equal("AllocationMarker" in saveHeapSnapshotAndTakeCensus(dbg).objects, false,
         "No allocation markers should exist in the census.");
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_06.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_06.js
index 0412410c0d4b..d69c5a01d1af 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_06.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_06.js
@@ -1,88 +1,91 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Check HeapSnapshot.prototype.takeCensus handling of 'breakdown' argument.
 //
 // Ported from js/src/jit-test/tests/debug/Memory-takeCensus-06.js
 
 function run_test() {
-  var Pattern = Match.Pattern;
+  let Pattern = Match.Pattern;
 
-  var g = newGlobal();
-  var dbg = new Debugger(g);
+  let g = newGlobal();
+  let dbg = new Debugger(g);
 
   Pattern({ count: Pattern.NATURAL,
             bytes: Pattern.NATURAL })
     .assert(saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "count" } }));
 
-  let census = saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "count", count: false, bytes: false } });
+  let census = saveHeapSnapshotAndTakeCensus(dbg,
+    { breakdown: { by: "count", count: false, bytes: false } });
   equal("count" in census, false);
   equal("bytes" in census, false);
 
-  census = saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "count", count: true, bytes: false } });
+  census = saveHeapSnapshotAndTakeCensus(dbg,
+    { breakdown: { by: "count", count: true, bytes: false } });
   equal("count" in census, true);
   equal("bytes" in census, false);
 
-  census = saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "count", count: false, bytes: true } });
+  census = saveHeapSnapshotAndTakeCensus(dbg,
+    { breakdown: { by: "count", count: false, bytes: true } });
   equal("count" in census, false);
   equal("bytes" in census, true);
 
-  census = saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "count", count: true, bytes: true } });
+  census = saveHeapSnapshotAndTakeCensus(dbg,
+    { breakdown: { by: "count", count: true, bytes: true } });
   equal("count" in census, true);
   equal("bytes" in census, true);
 
-
   // Pattern doesn't mind objects with extra properties, so we'll restrict this
   // list to the object classes we're pretty sure are going to stick around for
   // the forseeable future.
   Pattern({
-    Function:       { count: Pattern.NATURAL },
-    Object:         { count: Pattern.NATURAL },
-    Debugger:       { count: Pattern.NATURAL },
-    Sandbox:        { count: Pattern.NATURAL },
+    Function: { count: Pattern.NATURAL },
+    Object: { count: Pattern.NATURAL },
+    Debugger: { count: Pattern.NATURAL },
+    Sandbox: { count: Pattern.NATURAL },
 
             // The below are all Debugger prototype objects.
-    Source:         { count: Pattern.NATURAL },
-    Environment:    { count: Pattern.NATURAL },
-    Script:         { count: Pattern.NATURAL },
-    Memory:         { count: Pattern.NATURAL },
-    Frame:          { count: Pattern.NATURAL }
+    Source: { count: Pattern.NATURAL },
+    Environment: { count: Pattern.NATURAL },
+    Script: { count: Pattern.NATURAL },
+    Memory: { count: Pattern.NATURAL },
+    Frame: { count: Pattern.NATURAL }
   })
     .assert(saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "objectClass" } }));
 
   Pattern({
-    objects:        { count: Pattern.NATURAL },
-    scripts:        { count: Pattern.NATURAL },
-    strings:        { count: Pattern.NATURAL },
-    other:          { count: Pattern.NATURAL }
+    objects: { count: Pattern.NATURAL },
+    scripts: { count: Pattern.NATURAL },
+    strings: { count: Pattern.NATURAL },
+    other: { count: Pattern.NATURAL }
   })
     .assert(saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "coarseType" } }));
 
   // As for { by: 'objectClass' }, restrict our pattern to the types
   // we predict will stick around for a long time.
   Pattern({
-    JSString:             { count: Pattern.NATURAL },
-    "js::Shape":          { count: Pattern.NATURAL },
-    JSObject:             { count: Pattern.NATURAL },
-    JSScript:             { count: Pattern.NATURAL }
+    JSString: { count: Pattern.NATURAL },
+    "js::Shape": { count: Pattern.NATURAL },
+    JSObject: { count: Pattern.NATURAL },
+    JSScript: { count: Pattern.NATURAL }
   })
     .assert(saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "internalType" } }));
 
-
   // Nested breakdowns.
 
   let coarseTypePattern = {
-    objects:        { count: Pattern.NATURAL },
-    scripts:        { count: Pattern.NATURAL },
-    strings:        { count: Pattern.NATURAL },
-    other:          { count: Pattern.NATURAL }
+    objects: { count: Pattern.NATURAL },
+    scripts: { count: Pattern.NATURAL },
+    strings: { count: Pattern.NATURAL },
+    other: { count: Pattern.NATURAL }
   };
 
   Pattern({
-    JSString:    coarseTypePattern,
+    JSString: coarseTypePattern,
     "js::Shape": coarseTypePattern,
-    JSObject:    coarseTypePattern,
-    JSScript:    coarseTypePattern,
+    JSObject: coarseTypePattern,
+    JSScript: coarseTypePattern,
   })
     .assert(saveHeapSnapshotAndTakeCensus(dbg, {
       breakdown: { by: "internalType",
@@ -91,16 +94,16 @@ function run_test() {
     }));
 
   Pattern({
-    Function:       { count: Pattern.NATURAL },
-    Object:         { count: Pattern.NATURAL },
-    Debugger:       { count: Pattern.NATURAL },
-    Sandbox:        { count: Pattern.NATURAL },
-    other:          coarseTypePattern
+    Function: { count: Pattern.NATURAL },
+    Object: { count: Pattern.NATURAL },
+    Debugger: { count: Pattern.NATURAL },
+    Sandbox: { count: Pattern.NATURAL },
+    other: coarseTypePattern
   })
     .assert(saveHeapSnapshotAndTakeCensus(dbg, {
       breakdown: {
         by: "objectClass",
-        then:  { by: "count" },
+        then: { by: "count" },
         other: { by: "coarseType" }
       }
     }));
@@ -109,7 +112,7 @@ function run_test() {
     objects: { count: Pattern.NATURAL, label: "object" },
     scripts: { count: Pattern.NATURAL, label: "scripts" },
     strings: { count: Pattern.NATURAL, label: "strings" },
-    other:   { count: Pattern.NATURAL, label: "other" }
+    other: { count: Pattern.NATURAL, label: "other" }
   })
     .assert(saveHeapSnapshotAndTakeCensus(dbg, {
       breakdown: {
@@ -117,7 +120,7 @@ function run_test() {
         objects: { by: "count", label: "object" },
         scripts: { by: "count", label: "scripts" },
         strings: { by: "count", label: "strings" },
-        other:   { by: "count", label: "other" }
+        other: { by: "count", label: "other" }
       }
     }));
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_07.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_07.js
index f5c36056f617..b6fcbd59ff7f 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_07.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_07.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // HeapSnapshot.prototype.takeCensus breakdown: check error handling on property
 // gets.
@@ -7,74 +8,86 @@
 // Ported from js/src/jit-test/tests/debug/Memory-takeCensus-07.js
 
 function run_test() {
-  var g = newGlobal();
-  var dbg = new Debugger(g);
+  let g = newGlobal();
+  let dbg = new Debugger(g);
 
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { get by() { throw "ಠ_ಠ"; } }
+      breakdown: { get by() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-
-
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "count", get count() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "count", get count() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "count", get bytes() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "count", get bytes() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-
-
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "objectClass", get then() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "objectClass", get then() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "objectClass", get other() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "objectClass", get other() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-
-
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "coarseType", get objects() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "coarseType", get objects() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "coarseType", get scripts() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "coarseType", get scripts() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "coarseType", get strings() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "coarseType", get strings() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "coarseType", get other() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "coarseType", get other() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
-
-
-  assertThrowsValue(() => {
+  assertThrows(() => {
     saveHeapSnapshotAndTakeCensus(dbg, {
-      breakdown: { by: "internalType", get then() { throw "ಠ_ಠ"; } }
+      breakdown: { by: "internalType", get then() {
+        throw Error("ಠ_ಠ");
+      } }
     });
   }, "ಠ_ಠ");
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_08.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_08.js
index 5934aa919026..4b70a8f9e15e 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_08.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_08.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // HeapSnapshot.prototype.takeCensus: test by: 'count' breakdown
 //
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_09.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_09.js
index bbacccc8ddc5..bb44b643cdec 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_09.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_09.js
@@ -1,20 +1,21 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // HeapSnapshot.prototype.takeCensus: by: allocationStack breakdown
 //
 // Ported from js/src/jit-test/tests/debug/Memory-takeCensus-09.js
 
 function run_test() {
-  var g = newGlobal();
-  var dbg = new Debugger(g);
+  let g = newGlobal();
+  let dbg = new Debugger(g);
 
   g.eval(`                                              // 1
          var log = [];                                  // 2
          function f() { log.push(allocationMarker()); } // 3
          function g() { f(); }                          // 4
          function h() { f(); }                          // 5
-         `);                                            // 6
+         `);
 
   // Create one allocationMarker with tracking turned off,
   // so it will have no associated stack.
@@ -22,7 +23,7 @@ function run_test() {
 
   dbg.memory.allocationSamplingProbability = 1;
 
-  for ([func, n] of [[g.f, 20], [g.g, 10], [g.h, 5]]) {
+  for (let [func, n] of [[g.f, 20], [g.g, 10], [g.h, 5]]) {
     for (let i = 0; i < n; i++) {
       dbg.memory.trackingAllocationSites = true;
       // All allocations of allocationMarker occur with this line as the oldest
@@ -32,17 +33,19 @@ function run_test() {
     }
   }
 
-  let census = saveHeapSnapshotAndTakeCensus(dbg, { breakdown: { by: "objectClass",
-                                                                 then: { by: "allocationStack",
-                                                                         then: { by: "count",
-                                                                                 label: "haz stack"
-                                                                               },
-                                                                         noStack: { by: "count",
-                                                                                    label: "no haz stack"
-                                                                                  }
-                                                                       }
-                                                               }
-                                                  });
+  let census = saveHeapSnapshotAndTakeCensus(
+    dbg, { breakdown: {
+      by: "objectClass",
+      then: {
+        by: "allocationStack",
+        then: { by: "count", label: "haz stack"},
+        noStack: {
+          by: "count",
+          label: "no haz stack"
+        }
+      }
+    }
+    });
 
   let map = census.AllocationMarker;
   ok(map instanceof Map, "Should be a Map instance");
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_10.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_10.js
index a7f987f5a22d..0cd21962e058 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_10.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_10.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Check byte counts produced by takeCensus.
 //
@@ -25,7 +26,7 @@ function run_test() {
            for (let i = 0; i < 10; i++)     // 5
              objs.push(allocationMarker()); // 6
          }                                  // 7
-         `);                                // 8
+         `);
 
   dbg.memory.allocationSamplingProbability = 1;
   dbg.memory.trackingAllocationSites = true;
@@ -35,7 +36,7 @@ function run_test() {
   census = saveHeapSnapshotAndTakeCensus(dbg, {
     breakdown: { by: "objectClass",
                  then: { by: "allocationStack" }
-               }
+    }
   });
 
   let seen = 0;
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_11.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_11.js
index 3d898b2d191b..aa89ab2fe461 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_11.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_11.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that Debugger.Memory.prototype.takeCensus and
 // HeapSnapshot.prototype.takeCensus return the same data for the same heap
@@ -14,7 +15,7 @@ function doLiveAndOfflineCensus(g, dbg, opts) {
              this.markers.push(allocationMarker()); // 4
            }                                        // 5
          }());                                      // 6
-         `);                                        // 7
+         `);
   dbg.memory.trackingAllocationSites = false;
 
   return {
@@ -24,8 +25,8 @@ function doLiveAndOfflineCensus(g, dbg, opts) {
 }
 
 function run_test() {
-  var g = newGlobal();
-  var dbg = new Debugger(g);
+  let g = newGlobal();
+  let dbg = new Debugger(g);
 
   g.eval("this.markers = []");
   const markerSize = byteSize(allocationMarker());
@@ -36,7 +37,7 @@ function run_test() {
   let prevCount = 0;
   let prevBytes = 0;
 
-  for (var i = 0; i < 10; i++) {
+  for (let i = 0; i < 10; i++) {
     const { live, offline } = doLiveAndOfflineCensus(g, dbg, {
       breakdown: { by: "objectClass",
                    then: { by: "count"} }
@@ -96,9 +97,8 @@ function run_test() {
       return -1;
     } else if (a[0] > b[0]) {
       return 1;
-    } else {
-      return 0;
     }
+    return 0;
   };
   liveEntries.sort(sortEntries);
   offlineEntries.sort(sortEntries);
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_12.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_12.js
index f10dd5b03432..5f4ac2c8ac15 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_12.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_takeCensus_12.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that when we take a census and get a bucket list of ids that matched the
 // given category, that the returned ids are all in the snapshot and their
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot.js b/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot.js
index dde139ffd2db..ce437d10e4a7 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot.js
@@ -2,7 +2,7 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test that we can read core dumps into HeapSnapshot instances.
-
+/* eslint-disable strict */
 if (typeof Debugger != "function") {
   const { addDebuggerToGlobal } = Cu.import("resource://gre/modules/jsdebugger.jsm", {});
   addDebuggerToGlobal(this);
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot_with_allocations.js b/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot_with_allocations.js
index d91f36f5654b..e60bc8c984c0 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot_with_allocations.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot_with_allocations.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that we can save a core dump with allocation stacks and read it back
 // into a HeapSnapshot.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot_worker.js b/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot_worker.js
index 5d431cb52640..d782a67ac68f 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot_worker.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_ReadHeapSnapshot_worker.js
@@ -2,7 +2,7 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test that we can read core dumps into HeapSnapshot instances in a worker.
-
+// eslint-disable-next-line
 add_task(function* () {
   const worker = new ChromeWorker("resource://test/heap-snapshot-worker.js");
   worker.postMessage({});
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_SaveHeapSnapshot.js b/devtools/shared/heapsnapshot/tests/unit/test_SaveHeapSnapshot.js
index affd8d1e47cf..abdb8b139973 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_SaveHeapSnapshot.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_SaveHeapSnapshot.js
@@ -2,7 +2,7 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test the ChromeUtils interface.
-
+// eslint-disable-next-line
 if (typeof Debugger != "function") {
   const { addDebuggerToGlobal } = Cu.import("resource://gre/modules/jsdebugger.jsm", {});
   addDebuggerToGlobal(this);
@@ -49,8 +49,9 @@ function testBadParameters() {
   throws(() => ChromeUtils.saveHeapSnapshot({ debugger: Debugger.prototype }),
          "Should throw if debugger is the Debugger.prototype object.");
 
-  throws(() => ChromeUtils.saveHeapSnapshot({ get globals() { return [this]; } }),
-         "Should throw if boundaries property is a getter.");
+  throws(() => ChromeUtils.saveHeapSnapshot({ get globals() {
+    return [this];
+  } }), "Should throw if boundaries property is a getter.");
 }
 
 const makeNewSandbox = () =>
@@ -63,14 +64,14 @@ function testGoodParameters() {
   ChromeUtils.saveHeapSnapshot({ debugger: dbg });
   ok(true, "Should be able to save a snapshot for a debuggee global.");
 
-  dbg = new Debugger;
+  dbg = new Debugger();
   let sandboxes = Array(10).fill(null).map(makeNewSandbox);
   sandboxes.forEach(sb => dbg.addDebuggee(sb));
 
   ChromeUtils.saveHeapSnapshot({ debugger: dbg });
   ok(true, "Should be able to save a snapshot for many debuggee globals.");
 
-  dbg = new Debugger;
+  dbg = new Debugger();
   ChromeUtils.saveHeapSnapshot({ debugger: dbg });
   ok(true, "Should be able to save a snapshot with no debuggee globals.");
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-01.js b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-01.js
index 16038c5c499c..c2a8f00523ae 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 /**
  * Tests CensusTreeNode with `internalType` breakdown.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-02.js b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-02.js
index 37d039954280..0caa5ea88fd9 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 /**
  * Tests CensusTreeNode with `coarseType` breakdown.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-03.js b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-03.js
index bdf932099c74..b3f083de0c88 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 /**
  * Tests CensusTreeNode with `objectClass` breakdown.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-04.js b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-04.js
index cc0c3bac03e8..50e7eae8b4a6 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-04.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-04.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 /**
  * Tests CensusTreeNode with `allocationStack` breakdown.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-05.js b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-05.js
index 20fb76bd2fa8..3a0ebc71ada0 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-05.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-05.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 /**
  * Tests CensusTreeNode with `allocationStack` => `objectClass` breakdown.
@@ -29,11 +30,11 @@ function run_test() {
   }());
 
   const REPORT = new Map([
-    [stack, { Foo:   { bytes: 10, count: 1 },
-                  Bar:   { bytes: 20, count: 2 },
-                  Baz:   { bytes: 30, count: 3 },
-                  other: { bytes: 40, count: 4 }
-                }],
+    [stack, { Foo: { bytes: 10, count: 1 },
+              Bar: { bytes: 20, count: 2 },
+              Baz: { bytes: 30, count: 3 },
+              other: { bytes: 40, count: 4 }
+    }],
     ["noStack", { bytes: 50, count: 5 }],
   ]);
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-06.js b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-06.js
index eb180120720d..5d1aee48f8cc 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-06.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-06.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 /**
  * Test inverting CensusTreeNode with a by alloaction stack breakdown.
@@ -12,8 +13,6 @@ function run_test() {
     noStack: { by: "count", count: true, bytes: true },
   };
 
-  let stack1, stack2, stack3, stack4;
-
   function a(n) {
     return b(n);
   }
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-07.js b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-07.js
index 6bc085257718..fcb557da966f 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-07.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-07.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 /**
  * Test inverting CensusTreeNode with a non-allocation stack breakdown.
@@ -21,7 +22,7 @@ function run_test() {
       by: "internalType",
       then: { by: "count", count: true, bytes: true },
     },
-    other:{
+    other: {
       by: "internalType",
       then: { by: "count", count: true, bytes: true },
     },
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-08.js b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-08.js
index 1c686c810249..0c6fe670b6f5 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-08.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census-tree-node-08.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 /**
  * Test inverting CensusTreeNode with a non-allocation stack breakdown.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_01.js b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_01.js
index 75977bccb183..5cfd001dfea9 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test diffing census reports of breakdown by "internalType".
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_02.js b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_02.js
index 169e3f036866..d5b2c21c18ce 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test diffing census reports of breakdown by "count".
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_03.js b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_03.js
index 6dbca3e40f8a..a564c0ba074c 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test diffing census reports of breakdown by "coarseType".
 
@@ -8,7 +9,7 @@ const BREAKDOWN = {
   objects: { by: "count", count: true, bytes: true },
   scripts: { by: "count", count: true, bytes: true },
   strings: { by: "count", count: true, bytes: true },
-  other:   { by: "count", count: true, bytes: true },
+  other: { by: "count", count: true, bytes: true },
 };
 
 const REPORT1 = {
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_04.js b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_04.js
index a10097945f15..2ffa4e6dca1b 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_04.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_04.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test diffing census reports of breakdown by "objectClass".
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_05.js b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_05.js
index b6d99f8239a6..ae5bfc2f576b 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_05.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_05.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test diffing census reports of breakdown by "allocationStack".
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_06.js b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_06.js
index 430ff8c9c70d..1833ebb11566 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_diff_06.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_diff_06.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test diffing census reports of a "complex" and "realistic" breakdown.
 
@@ -41,11 +42,11 @@ const REPORT1 = {
     [stack1, { Function: { bytes: 1 },
                Object: { bytes: 2 },
                other: { bytes: 0 },
-             }],
+    }],
     [stack2, { Array: { bytes: 3 },
                Date: { bytes: 4 },
                other: { bytes: 0 },
-             }],
+    }],
     ["noStack", { Object: { bytes: 3 }}],
   ]),
   strings: {
@@ -66,11 +67,11 @@ const REPORT2 = {
     [stack2, { Array: { bytes: 1 },
                Date: { bytes: 2 },
                other: { bytes: 3 },
-             }],
+    }],
     [stack3, { Function: { bytes: 1 },
                Object: { bytes: 2 },
                other: { bytes: 0 },
-             }],
+    }],
     ["noStack", { Object: { bytes: 3 }}],
   ]),
   strings: {
@@ -92,15 +93,15 @@ const EXPECTED = {
     [stack1, { Function: { bytes: -1 },
                Object: { bytes: -2 },
                other: { bytes: 0 },
-             }],
+    }],
     [stack2, { Array: { bytes: -2 },
                Date: { bytes: -2 },
                other: { bytes: 3 },
-             }],
+    }],
     [stack3, { Function: { bytes: 1 },
                Object: { bytes: 2 },
                other: { bytes: 0 },
-             }],
+    }],
     ["noStack", { Object: { bytes: 0 }}],
   ]),
   "scripts": {
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_01.js b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_01.js
index 57724d7c1f19..29da7ccdfede 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test filtering basic CensusTreeNode trees.
 
@@ -19,7 +20,7 @@ function run_test() {
       by: "internalType",
       then: { by: "count", count: true, bytes: true },
     },
-    other:{
+    other: {
       by: "internalType",
       then: { by: "count", count: true, bytes: true },
     },
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_02.js b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_02.js
index 0a57ce66dc97..19920d1a5c10 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_02.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_02.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test filtering CensusTreeNode trees with an `allocationStack` breakdown.
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_03.js b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_03.js
index 2c69a14b82f1..60e123e5ffe7 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_03.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_03.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test filtering with no matches.
 
@@ -19,7 +20,7 @@ function run_test() {
       by: "internalType",
       then: { by: "count", count: true, bytes: true },
     },
-    other:{
+    other: {
       by: "internalType",
       then: { by: "count", count: true, bytes: true },
     },
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_04.js b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_04.js
index c9871436b864..529c5378dde4 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_04.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_04.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test the filtered nodes' counts and bytes are the same as they were when
 // unfiltered.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_05.js b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_05.js
index 1d1f4fa550b4..f13c9976dc49 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_05.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_census_filtering_05.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test that filtered and inverted allocation stack census trees are sorted
 // properly.
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_getCensusIndividuals_01.js b/devtools/shared/heapsnapshot/tests/unit/test_getCensusIndividuals_01.js
index 9c4f60991a99..77d15dca5ecb 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_getCensusIndividuals_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_getCensusIndividuals_01.js
@@ -1,6 +1,7 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
+// eslint-disable no-inline-comments
 
 // Test basic functionality of `CensusUtils.getCensusIndividuals`.
 
@@ -24,6 +25,7 @@ function run_test() {
         breakdown,
         CensusUtils.countToBucketBreakdown(BREAKDOWN));
 
+      /* eslint-disable */
       //                                DFS Index
       return new Map([               // 0
         [stack1, {                   // 1
@@ -43,6 +45,7 @@ function run_test() {
           JSString: [411, 412, 413], // 12
         }],
       ]);
+      /* eslint-enable */
     }
   };
 
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_getReportLeaves_01.js b/devtools/shared/heapsnapshot/tests/unit/test_getReportLeaves_01.js
index 4c4298b6ad52..b69e9be116fb 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_getReportLeaves_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_getReportLeaves_01.js
@@ -63,7 +63,8 @@ function run_test() {
       const [ leaf ] = CensusUtils.getReportLeaves(new Set([node.reportLeafIndex]),
                                                    BREAKDOWN,
                                                    REPORT);
-      ok(leaf, "Should be able to find leaf for a node with a reportLeafIndex = " + node.reportLeafIndex);
+      ok(leaf, "Should be able to find leaf "
+        + "for a node with a reportLeafIndex = " + node.reportLeafIndex);
     }
 
     if (node.children) {
@@ -88,6 +89,8 @@ function run_test() {
         }
       }
     }
+
+    return undefined;
   }
 
   const arrayNode = find("Array", root);
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_saveHeapSnapshot_e10s_01.js b/devtools/shared/heapsnapshot/tests/unit/test_saveHeapSnapshot_e10s_01.js
index 067b9effbd5f..1cb323720b2e 100644
--- a/devtools/shared/heapsnapshot/tests/unit/test_saveHeapSnapshot_e10s_01.js
+++ b/devtools/shared/heapsnapshot/tests/unit/test_saveHeapSnapshot_e10s_01.js
@@ -1,5 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
 
 // Test saving a heap snapshot in the sandboxed e10s child process.