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

You could solve this problem using Number as iteratee function:

var a = ['0', '1', '2', '10', '15', '57'].map(Number);

console.log(a);

Without the new operator, Number can be used to perform type conversion. However, it differs from parseInt: it doesn't parse the string and returns NaN if the number cannot be converted. For instance:

console.log(parseInt("19asdf"));
console.log(Number("19asf"));