Number() constructor
The Number()
constructor creates a Number
object. When called instead as a function, it performs type conversion to a primitive number, which is usually more useful.
Syntax
new Number(value)
Number(value)
Note: Number()
can be called with or without new
, but with different effects. See Return value.
Parameters
value
-
The numeric value of the object being created.
Return value
When Number
is called as a constructor (with new
), it creates a Number
object, which is not a primitive.
When Number
is called as a function, it coerces the parameter to a number primitive. If the value can't be converted, it returns NaN
.
Warning: You should rarely find yourself using Number
as a constructor.
Examples
Creating Number objects
const a = new Number('123'); // a === 123 is false
const b = Number('123'); // b === 123 is true
a instanceof Number; // is true
b instanceof Number; // is false
typeof a // "object"
typeof b // "number"
Specifications
Specification |
---|
ECMAScript Language Specification # sec-number-constructor |
Browser compatibility
BCD tables only load in the browser
See also
- Polyfill of modern
Number
behavior (with support binary and octal literals) incore-js
NaN
- The
Math
global object - Integers with arbitrary precision:
BigInt