gecko-dev/testing/web-platform/tests/encoding/textdecoder-copy.any.js

test(() => {
  const buf = new ArrayBuffer(2),
        view = new Uint8Array(buf),
        buf2 = new ArrayBuffer(2),
        view2 = new Uint8Array(buf2),
        decoder = new TextDecoder("utf-8")
  view[0] = 0xEF
  view[1] = 0xBB
  view2[0] = 0xBF
  view2[1] = 0x40
  assert_equals(decoder.decode(buf, {stream:true}), "")
  view[0] = 0x01
  view[1] = 0x02
  assert_equals(decoder.decode(buf2), "@")
}, "Modify buffer after passing it in")