tor-browser

The Tor Browser
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yield-star-getiter-async-throw-method-is-null.js (1957B)

      1 // |reftest| async
      2 // Copyright (C) 2020 Alexey Shvayka. All rights reserved.
      3 // This code is governed by the BSD license found in the LICENSE file.
      4 /*---
      5 esid: sec-generator-function-definitions-runtime-semantics-evaluation
      6 description: >
      7  If iterator's "throw" method is `null`,
      8  AsyncIteratorClose is called before rising TypeError.
      9 info: |
     10  YieldExpression : yield * AssignmentExpression
     11 
     12  [...]
     13  7. Repeat,
     14    [...]
     15    b. Else if received.[[Type]] is throw, then
     16      i. Let throw be ? GetMethod(iterator, "throw").
     17      ii. If throw is not undefined, then
     18        [...]
     19      iii. Else,
     20        [...]
     21        3. If generatorKind is async, perform ? AsyncIteratorClose(iteratorRecord, closeCompletion).
     22        [...]
     23        6. Throw a TypeError exception.
     24 
     25  GetMethod ( V, P )
     26 
     27  [...]
     28  2. Let func be ? GetV(V, P).
     29  3. If func is either undefined or null, return undefined.
     30 
     31  AsyncIteratorClose ( iteratorRecord, completion )
     32 
     33  [...]
     34  4. Let innerResult be GetMethod(iterator, "return").
     35  5. If innerResult.[[Type]] is normal, then
     36    a. Let return be innerResult.[[Value]].
     37    b. If return is undefined, return Completion(completion).
     38 features: [Symbol.asyncIterator, async-iteration]
     39 flags: [async]
     40 ---*/
     41 
     42 var throwGets = 0;
     43 var returnGets = 0;
     44 var asyncIterable = {
     45  [Symbol.asyncIterator]: function() {
     46    return this;
     47  },
     48  next: function() {
     49    return {value: 1, done: false};
     50  },
     51  get throw() {
     52    throwGets += 1;
     53    return null;
     54  },
     55  get return() {
     56    returnGets += 1;
     57  },
     58 };
     59 
     60 async function* asyncGenerator() {
     61  yield* asyncIterable;
     62 }
     63 
     64 var asyncIterator = asyncGenerator();
     65 asyncIterator.next().then(function() {
     66  return asyncIterator.throw();
     67 }).then(function(result) {
     68  throw new Test262Error("Promise should be rejected, got: " + result.value);
     69 }, function(err) {
     70  assert.sameValue(err.constructor, TypeError);
     71  assert.sameValue(throwGets, 1);
     72  assert.sameValue(returnGets, 1);
     73 }).then($DONE, $DONE);