for in and for of do completely different things and there is no reason to expect consistency between them.
This was discussed already; search esdiscuss.org. On Dec 22, 2014 8:37 AM, Glen Huang <[email protected]> wrote: In that case we have a gotcha. Is there any interest to change that behavior? Since es6 isn’t finial yet. On Dec 22, 2014, at 9:29 PM, Gary Guo <[email protected]<mailto:[email protected]>> wrote: On Mon, 22 Dec 2014 21:06:18 +0800, Glen Huang <[email protected]<mailto:[email protected]>> wrote: >Ideally it shouldn’t, because its twin `for (var a in null) {}` won’t. > >But looking at step 8 in >https://people.mozilla.org/~jorendorff/es6-draft.html#sec-runtime-semantics-forin-div-ofexpressionevaluation-abstract-operation, > when passing `null` to `GetIterator()`, it will throw a type error when the >result of step 2 `CheckIterable(null)`, which is `undefind`, is called in step >3 in the algorithm for `GetIterator()`. > >Did I miss something or the current spec does throw an error? To me since `IsCallable(undefined)` is `false`, so it throws an `TypeError`. Traceur and V8 will both throw a `TypeError` saying that cannot read property @@iterator from undefined or null, and Firefox throws a `TypeError` saying that null have no property. So it should be an error.
_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
