What is the difference between “new Number(…)” and “Number(…)” in JavaScript?

Question

In Javascript, one of the reliable ways to convert a string to a number is the Number constructor:

var x = Number(\'09\'); // 9, because it defa         


        

Answer 1

In the first case, you are using the Number Constructor Called as a Function, as described in the Specification, that will simply perform a type conversion, returning you a Number primitive.

In the second case, you are using the Number Constructor to make a Number object:

var x = Number('09');
typeof x; // 'number'

var x = new Number('09');
typeof x; // 'object'

Number('1') === new Number('1'); // false

The difference may be subtle, but I think it's important to notice how wrapper objects act on primitive values.