# mrienstra

Membro desde

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### in operator

Minor: linking a mention of `undefined` to the corresponding page.

### undefined

Code sample line length was too long to be visible (as far as I could tell, at many common browser window sizes) (PS: would be nice if the preview showed that)

### undefined

`undefined` is not a reserved word. The `void` operator is an alternative way to test for `undefined`. Hat tip to George "shapeshed" Ornbo.