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null
The value null represents the intentional absence of any object value. It is one of JavaScript’s primitive values and is treated as falsy for boolean operations.
Try it 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 isNaN(1 + null) // false isNaN(1 + undefined) // true Specifications Specification ECMAScript Language Specification # sec-null-value Browser compatibility
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Last modified: May 22, 2022, by MDN contributors
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