The goog.labs.object Namespace

.is(v, v2)

Whether two values are not observably distinguishable. This correctly detects that 0 is not the same as -0 and two NaNs are practically equivalent. The implementation is as suggested by harmony:egal proposal.

v {*}
The first value to compare.
v2 {*}
The second value to compare.
returns {boolean}
Whether two values are not observably distinguishable.
@see
http://wiki.ecmascript.org/doku.php?id=harmony:egal