Math.abs

The Math.abs() function returns the absolute value of a number, that is

$${\mathtt{\operatorname{Math.abs}(x)}} = {|x|} = \begin{cases} x & \text{if} \quad x \geq 0 \\ -x & \text{if} \quad x < 0 \end{cases}$$

Syntax

Math.abs(x)

Parameters

x

A number.

Return value

The absolute value of the given number.

Description

Because abs() is a static method of Math, you always use it as Math.abs(), rather than as a method of a Math object you created (Math is not a constructor).

Examples

Behavior of Math.abs()

Passing an empty object, an array with more than one member, a non-numeric string or undefined/empty variable returns NaN. Passing null, an empty string or an empty array returns 0.

Math.abs('-1');     // 1
Math.abs(-2);       // 2
Math.abs(null);     // 0
Math.abs('');       // 0
Math.abs([]);       // 0
Math.abs([2]);      // 2
Math.abs([1,2]);    // NaN
Math.abs({});       // NaN
Math.abs('string'); // NaN
Math.abs();         // NaN

Specifications

Specification	Status	Comment
ECMAScript 1st Edition (ECMA-262)	Standard	Initial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262) The definition of 'Math.abs' in that specification.	Standard
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Math.abs' in that specification.	Standard
ECMAScript 2017 Draft (ECMA-262) The definition of 'Math.abs' in that specification.	Draft

Browser compatibility

See also

• Math.ceil()
• Math.floor()
• Math.round()
• Math.sign()
• Math.trunc()