The strict inequality operator (!==
) checks whether its two operands are not equal, returning a Boolean result. Unlike the inequality operator, the strict inequality operator always considers operands of different types to be different.
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Syntax
x !== y
Description
The strict inequality operator checks whether its operands are not equal. It is the negation of the strict equality operator so the following two lines will always give the same result:
x !== y !(x === y)
For details of the comparison algorithm, see the page for the strict equality operator.
Like the strict equality operator, the strict inequality operator will always consider operands of different types to be different:
3 !== "3"; // true
Examples
Comparing operands of the same type
console.log("hello" !== "hello"); // false console.log("hello" !== "hola"); // true console.log(3 !== 3); // false console.log(3 !== 4); // true console.log(true !== true); // false console.log(true !== false); // true console.log(null !== null); // false
Comparing operands of different types
console.log("3" !== 3); // true console.log(true !== 1); // true console.log(null !== undefined); // true
Comparing objects
const object1 = { name: "hello" } const object2 = { name: "hello" } console.log(object1 !== object2); // true console.log(object1 !== object1); // false
Specifications
Specification |
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ECMAScript (ECMA-262) The definition of 'Equality operators' in that specification. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Strict inequality (a !== b ) | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 4 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
Legend
- Full support
- Full support