The Number()
creates a Number
object. When called instead as a function, it performs type conversion to a primitive number, which is usually more useful.
The Number()
creates a Number
object. When called instead as a function, it performs type conversion to a primitive number, which is usually more useful.
new Number(value) Number(value)
Note: Number()
can be called with or without new
, but with different effects. See Return value.
value
The numeric value of the object being created.
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.
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"
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | Deno | Node.js | |
Number |
1 |
12 |
1 |
3 |
3 |
1 |
4.4 |
18 |
4 |
10.1 |
1 |
1.0 |
1.0 |
0.10.0 |
Number
behavior (with support binary and octal literals) in core-js
NaN
Math
global objectBigInt
© 2005–2022 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/Number