jashkenas/underscore — pull request #1331 by hopehopehope (2013-11-06 11:05:22+00:00)
Title: Update underscore.js

in _.each function:
The test for the argument "obj" to be an Array has been
if (obj.length === +obj.length)

This seems unfortunatelly not to be the best test since this
var obj = {length:1}
is not an Array, but will be taken for one (and hence break _.each)

An alternative test criteria which would avoid this problem is:
if (Object.prototype.toString.call( obj ) === '[object Array]')