Lib definition for isNaN wrong

[eseliger]

Code

isNaN(0)
isNaN('120')
isNaN(new Date())

Expected behavior:
isNaN should also take string and Date and pretty much everything, probably any
See here in the examples section

Actual behavior:
It only takes number https://github.com/Microsoft/TypeScript/blob/master/lib/lib.es5.d.ts#L53

[trotyl]

It's by design, see #3947, #4002, #11414, #13227, #15173, #16427.

[RyanCavanaugh]

@eseliger please do read the instructions and search for existing issues before logging new ones