Source code
Revision control
Copy as Markdown
Other Tools
// |reftest| async
// This file was procedurally generated from the following sources:
// - src/dstr-assignment-for-await/array-elem-trlg-iter-elision-iter-nrml-close-null.case
// - src/dstr-assignment-for-await/default/async-func-decl.template
/*---
description: IteratorClose throws a TypeError when `return` returns a non-Object value (for-await-of statement in an async function declaration)
esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
features: [Symbol.iterator, destructuring-binding, async-iteration]
flags: [generated, async]
info: |
IterationStatement :
for await ( LeftHandSideExpression of AssignmentExpression ) Statement
1. Let keyResult be the result of performing ? ForIn/OfHeadEvaluation(« »,
AssignmentExpression, iterate).
2. Return ? ForIn/OfBodyEvaluation(LeftHandSideExpression, Statement,
keyResult, assignment, labelSet).
13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation
[...]
5. If destructuring is true and if lhsKind is assignment, then
a. Assert: lhs is a LeftHandSideExpression.
b. Let assignmentPattern be the parse of the source text corresponding to
lhs using AssignmentPattern as the goal symbol.
[...]
ArrayAssignmentPattern :
[ AssignmentElementList , Elisionopt AssignmentRestElementopt ]
[...]
6. If Elision is present, then
a. Let status be the result of performing
IteratorDestructuringAssignmentEvaluation of Elision with
iteratorRecord as the argument.
b. If status is an abrupt completion, then
[...]
8. If iteratorRecord.[[done]] is false, return IteratorClose(iterator,
status).
7.4.6 IteratorClose( iterator, completion )
[...]
6. Let innerResult be Call(return, iterator, « »).
7. If completion.[[type]] is throw, return Completion(completion).
8. If innerResult.[[type]] is throw, return Completion(innerResult).
9. If Type(innerResult.[[value]]) is not Object, throw a TypeError
exception.
---*/
let x;
let nextCount = 0;
let iterator = {
next() {
nextCount += 1;
// Set an upper-bound to limit unnecessary iteration in non-conformant
// implementations
return { done: nextCount > 10 };
},
return() {
return null;
}
};
let iterable = {
[Symbol.iterator]() {
return iterator;
}
};
let iterCount = 0;
async function fn() {
for await ([ x , , ] of [iterable]) {
iterCount += 1;
}
}
let promise = fn();
promise.then(() => $DONE('Promise incorrectly fulfilled.'), ({ constructor }) => {
assert.sameValue(iterCount, 0);
assert.sameValue(nextCount, 2);
assert.sameValue(constructor, TypeError);
}).then($DONE, $DONE);