tor-browser

The Tor Browser
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iterable-to-iterator-fallback.js (1022B)

      1 // Copyright (C) 2023 Michael Ficarra. All rights reserved.
      2 // This code is governed by the BSD license found in the LICENSE file.
      3 /*---
      4 esid: sec-iterator.from
      5 description: >
      6  Iterator.from falls back to treating its parameter as an iterator if the Symbol.iterator property is null/undefined
      7 info: |
      8  Iterator.from ( O )
      9 
     10 includes: [compareArray.js]
     11 features: [iterator-helpers]
     12 flags: []
     13 ---*/
     14 
     15 function* g() {
     16  yield 0;
     17  yield 1;
     18  yield 2;
     19 }
     20 
     21 let iter = (function () {
     22  let n = g();
     23  return {
     24    [Symbol.iterator]: 0,
     25    next: () => n.next(),
     26  };
     27 })();
     28 
     29 assert.throws(TypeError, function () {
     30  Iterator.from(iter);
     31 });
     32 
     33 iter = (function () {
     34  let n = g();
     35  return {
     36    [Symbol.iterator]: null,
     37    next: () => n.next(),
     38  };
     39 })();
     40 
     41 assert.compareArray(Array.from(Iterator.from(iter)), [0, 1, 2]);
     42 
     43 iter = (function () {
     44  let n = g();
     45  return {
     46    [Symbol.iterator]: undefined,
     47    next: () => n.next(),
     48  };
     49 })();
     50 
     51 assert.compareArray(Array.from(Iterator.from(iter)), [0, 1, 2]);
     52 
     53 reportCompare(0, 0);