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// Copyright (C) 2016 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-generator-function-definitions-runtime-semantics-evaluation
es6id: 14.4.14
description: >
`value` property is not accessed when iteration is incomplete
info: |
YieldExpression : yield * AssignmentExpression
1. Let exprRef be the result of evaluating AssignmentExpression.
2. Let value be ? GetValue(exprRef).
3. Let iterator be ? GetIterator(value).
4. Let received be NormalCompletion(undefined).
5. Repeat
a. If received.[[Type]] is normal, then
i. Let innerResult be ? IteratorNext(iterator, received.[[Value]]).
ii. Let done be ? IteratorComplete(innerResult).
iii. If done is true, then
1. Return ? IteratorValue(innerResult).
features: [generators, Symbol.iterator]
---*/
var badIter = {};
var callCount = 0;
var spyValue = Object.defineProperty({ done: false }, 'value', {
get: function() {
callCount += 1;
}
});
badIter[Symbol.iterator] = function() {
return {
next: function() {
return spyValue;
}
};
};
var delegationComplete = false;
function* g() {
yield * badIter;
delegationComplete = true;
}
var iter = g();
iter.next();
assert.sameValue(callCount, 0, 'access count (first iteration)');
assert.sameValue(
delegationComplete, false, 'delegation ongoing (first iteration)'
);
iter.next();
assert.sameValue(callCount, 0, 'access count (second iteration)');
assert.sameValue(
delegationComplete, false, 'delegation ongoing (second iteration)'
);
spyValue.done = true;
iter.next();
assert.sameValue(callCount, 1, 'access count (final iteration)');
assert.sameValue(delegationComplete, true, 'delegation complete');
reportCompare(0, 0);