Strict inequality (!==)

BaselineWidely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Thestrict inequality (!==) operator checks whether its two operands arenot equal, returning a Boolean result. Unlike theinequalityoperator, the strict inequality operator always considers operands of different types tobe different.

Try it

console.log(1 !== 1);// Expected output: falseconsole.log("hello" !== "hello");// Expected output: falseconsole.log("1" !== 1);// Expected output: trueconsole.log(0 !== false);// Expected output: true

Syntax

x !== y

Description

The strict inequality operator checks whether its operands are not equal.It is the negation of thestrict equality operatorso the following two lines will always give the same result:

x !== y;!(x === y);

For details of the comparison algorithm, see the page for thestrict equality operator.

Like the strict equality operator, the strict inequality operator will always consideroperands of different types to be different:

3 !== "3"; // true

Examples

Comparing operands of the same type

"hello" !== "hello"; // false"hello" !== "hola"; // true3 !== 3; // false3 !== 4; // truetrue !== true; // falsetrue !== false; // truenull !== null; // false

Comparing operands of different types

"3" !== 3; // truetrue !== 1; // truenull !== undefined; // true

Comparing objects

const object1 = {  key: "value",};const object2 = {  key: "value",};console.log(object1 !== object2); // trueconsole.log(object1 !== object1); // false