Converting a array of string to array of Int in JS

Question

I know I can do this:

a = ['1', '2']
b = []
a.forEach(function(e) { b.push(parseInt(e)); })
b
>> [1, 2]

I want to learn what is wrong in this?

['1', '2'].map(parseInt)
>> [1, NaN]

Answer 1

You can do that in the following way using map() by passing Number:

var res = ['1', '2'].map(Number)
console.log(res);