jquery/jquery — pull request #779 by mikaelkaron (2012-05-16 03:03:50+00:00)
Title: be more explicit about checking for null in $.map (#trac-11776)

quick copy-paste from the ticket:

Given

`console.log($.map([ 1, undefined, , 2, null, 3 ], function (e, i) { return e; }));`

results in

`[ 1, 2, 3 ]`

where I'd expect

`[ 1, undefined, undefined, 2, 3 ]`

Underlying problem is that we compare using `value != null` instead of `value !== null`