Strict inequality (!==) - JavaScript | MDN
Try it
console.log(1 !== 1);
// Expected output: false
console.log("hello" !== "hello");
// Expected output: false
console.log("1" !== 1);
// Expected output: true
console.log(0 !== false);
// Expected output: true
Syntax
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:
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:
Examples
Comparing operands of the same type
js
"hello" !== "hello"; // false
"hello" !== "hola"; // true
3 !== 3; // false
3 !== 4; // true
true !== true; // false
true !== false; // true
null !== null; // false
Comparing operands of different types
js
"3" !== 3; // true
true !== 1; // true
null !== undefined; // true
Comparing objects
js
const object1 = {
key: "value",
};
const object2 = {
key: "value",
};
console.log(object1 !== object2); // true
console.log(object1 !== object1); // false
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-equality-operators |