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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-isconcatspreadable
description: Revoked proxy value produces a TypeError when supplied to IsArray
info: |
[...]
5. Repeat, while items is not empty
a. Remove the first element from items and let E be the value of the
element.
b. Let spreadable be ? IsConcatSpreadable(E).
c. If spreadable is true, then
[...]
e. Else E is added as a single item rather than spread,
[...]
ES6 22.1.3.1.1: Runtime Semantics: IsConcatSpreadable ( O )
1. If Type(O) is not Object, return false.
2. Let spreadable be ? Get(O, @@isConcatSpreadable).
3. If spreadable is not undefined, return ToBoolean(spreadable).
4. Return ? IsArray(O).
7.2.2 IsArray
[...]
3. If argument is a Proxy exotic object, then
a. If the value of the [[ProxyHandler]] internal slot of argument is null,
throw a TypeError exception.
b. Let target be the value of the [[ProxyTarget]] internal slot of
argument.
c. Return ? IsArray(target).
features: [Proxy, Symbol.isConcatSpreadable]
---*/
var target = [];
var handle = Proxy.revocable(target, {
get: function(_, key) {
// Defer proxy revocation until after property access to ensure that the
// expected TypeError originates from the IsArray operation.
if (key === Symbol.isConcatSpreadable) {
handle.revoke();
}
return target[key];
}
});
assert.throws(TypeError, function() {
[].concat(handle.proxy);
}, '[].concat(handle.proxy) throws a TypeError exception');
reportCompare(0, 0);
|
