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// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-generator-function-definitions-runtime-semantics-evaluation
description: >
If <iterator>.throw is an object emulating `undefined` (e.g. `document.all`
in browsers), it shouldn't be treated as if it were actually `undefined` by
the yield* operator.
info: |
YieldExpression : yield * AssignmentExpression
[...]
7. Repeat,
[...]
b. Else if received.[[Type]] is throw, then
i. Let throw be ? GetMethod(iterator, "throw").
ii. If throw is not undefined, then
1. Let innerResult be ? Call(throw, iterator, « received.[[Value]] »).
[...]
4. If Type(innerResult) is not Object, throw a TypeError exception.
features: [generators, IsHTMLDDA]
---*/
var IsHTMLDDA = $262.IsHTMLDDA;
var returnCalls = 0;
var inner = {
[Symbol.iterator]() { return this; },
next() { return {done: false}; },
throw: IsHTMLDDA,
return() {
returnCalls += 1;
return {done: true};
},
};
var outer = (function* () { yield* inner; })();
outer.next();
assert.throws(TypeError, function() {
// `IsHTMLDDA` is called here with `iter` as `this` and `emptyString` as the
// sole argument, and it's specified to return `null` under these conditions.
// As `iter`'s iteration isn't ending because of a throw, the iteration
// protocol will then throw a `TypeError` because `null` isn't an object.
var emptyString = "";
outer.throw(emptyString);
});
assert.sameValue(returnCalls, 0);
reportCompare(0, 0);