typeof Number equals Number

Question

In JavaScript,

1. typeof 42 === 'number' //true

evaluates to true. But..

2. typeof Number === 'number' //false

evalutes to false. And..

3. typeof 'number' === 'number' //false

also evaluates to false.

Shouldn't comparison 2 or 3 evaluate to true?

Answer 1

No, Number , String , and Boolean are all objects (and functions). typeof applied to any of them will return the value "function" .

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean


The value 'number' is a string and therefore its type is 'string' .

Answer 2

Number is a function which you can use to wrap a native value into a Number object. Number is the also the constructor of the Number type, if used with new , eg

new Number(42)

From the documentation :

A Number object is created using the Number() constructor.

So typeof Number is actually "function" .

On the other hand, 'number' is a String, so typeof 'number' is "string"