Why does parseInt yield NaN with Array#map?

Question

From the Mozilla Developer Network:

[1,4,9].map(Math.sqrt)

will yield:

[1,2,3]

Why then does this:

<

Answer 1

map is passing along a 2nd argument, which is (in many of the cases) messing up parseInt's radix parameter.

If you're using underscore you can do:

['10','1','100'].map(_.partial(parseInt, _, 10))

Or without underscore:

['10','1','100'].map(function(x) { return parseInt(x, 10); });