>From <http://ecma-international.org/ecma-262/5.1/#sec-15.3.4.3> and
><http://ecma-international.org/ecma-262/5.1/#sec-15.3.4.4>:
> The `thisArg` value is passed without modification as the `this` value. This
> is a change from Edition 3, where a `undefined` or `null` `thisArg` is
> replaced with the global object and `ToObject` is applied to all other values
> and that result is passed as the `this` value.
It seems like modern engines still have the ES3 behavior:
function foo() {
console.log(this);
return this;
};
foo.call(undefined) === undefined; // `false`, expected `true`
I’ve tested this in Spidermonkey/Firefox, Carakan/PrestOpera, JSC/Safari, and
v8/Chrome. They all show FAIL in this test case:
data:text/html,<script>function foo() { console.log(this); return this; };
document.write(foo.call(undefined) === undefined %3F 'PASS' %3A
'FAIL');</script>
Is this…
1. a wilful violation of the ES5 spec for back-compat reasons, or…
2. is it just an oversight that this never got implemented, or…
3. am I misreading the spec?
If 1 is the case, the ES6 spec should match reality by reverting the change
introduced in ES5.
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