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null

The null value represents the intentional absence of any object value. It is one of JavaScript's primitive values and is treated as falsy for boolean operations.

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Syntax

null

Description

The value null is written with a literal: null. null is not an identifier for a property of the global object, like undefined can be. Instead, null expresses a lack of identification, indicating that a variable points to no object. In APIs, null is often retrieved in a place where an object can be expected but no object is relevant.

// foo does not exist. It is not defined and has never been initialized:
foo; //ReferenceError: foo is not defined

// foo is known to exist now but it has no type or value:
const foo = null;
foo; //null

Examples

Difference between `null` and `undefined`

When checking for null or undefined, beware of the differences between equality (==) and identity (===) operators, as the former performs type-conversion.

typeof null; // "object" (not "null" for legacy reasons)
typeof undefined; // "undefined"
null === undefined; // false
null == undefined; // true
null === null; // true
null == null; // true
!null; // true
Number.isNaN(1 + null); // false
Number.isNaN(1 + undefined); // true

Specifications

Specification
ECMAScript Language Specification # sec-null-value

Browser compatibility

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	Deno	Node.js
`null`	1	12	1	3	1	18	4	10.1	1	1.0	4.4	1.0	0.10.0