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Fix typeof Symbol.prototype #3686

Merged
merged 2 commits into from Sep 20, 2016
Merged

Fix typeof Symbol.prototype #3686

merged 2 commits into from Sep 20, 2016

Commits on Aug 30, 2016

  1. formatting

    @brainlock
    brainlock committed Aug 30, 2016
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  2. fix typeof Symbol.prototype 

    Babel uses a helper function to return the correct value for `typeof
obj` when obj is a Symbol and support for Symbol has been polyfilled.

This function assumes that `obj.constructor === Symbol` implies `typeof
obj === 'symbol'`.

This isn't true when obj is `Symbol.prototype`. In that case (REPL from
node 6, the same holds in Firefox):

```
> Symbol.prototype.constructor === Symbol
true
> typeof Symbol.prototype
'object'
>
```

AFAICS, that's the only case where the assumption doesn't hold.

The test added by this patch fails only on node 0.10, as 0.12 already
has a native implementation of Symbol and the polyfill code doesn't run.

This caused a problem in core-js when it's compiled with babel (the
issue was isolated by @skozin here:
zloirock/core-js#189 (comment)).
    @brainlock
    brainlock committed Aug 30, 2016
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