forked from mirrors/gecko-dev
36 lines
931 B
JavaScript
36 lines
931 B
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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// Simple event emitter abstraction for storage objects to use.
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export function EventEmitter() {
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this._events = new Map();
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}
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EventEmitter.prototype = {
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on(event, listener) {
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if (this._events.has(event)) {
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this._events.get(event).add(listener);
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} else {
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this._events.set(event, new Set([listener]));
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}
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},
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off(event, listener) {
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if (!this._events.has(event)) {
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return;
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}
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this._events.get(event).delete(listener);
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},
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emit(event, ...args) {
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if (!this._events.has(event)) {
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return;
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}
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for (let listener of this._events.get(event).values()) {
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try {
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listener.apply(this, args);
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} catch (e) {
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console.error(e);
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}
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}
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},
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};
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