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Home Interviews Describe the difference between == and === operators in JavaScript. – MindStick
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1 Answers

Ravi Vishwakarma
Ravi Vishwakarma 17 Jun 2024
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In JavaScript, '==' and '===' are both comparison operators, but they behave differently in terms of type oppression and strictness.

== (Equality Operator):

The ‘==’ operator performs type coercion if the operands are of different types. It converts the values to a common type before making the comparison. Because of type coercion, == is often referred to as a loose comparison operator.

console.log(5 == '5');        // true (number 5 is converted to string '5' or vice versa)
console.log(true == 1);       // true (boolean true is converted to number 1)
console.log(null == undefined); // true (null and undefined are considered equal)
console.log([] == '');        // true (empty array is converted to empty string)
console.log([1,2] == '1,2');  // true (array is converted to string '1,2')

=== (Strict Equality Operator):

The ‘===’ operator does not perform type coercion. It checks for both value and type equality. Because it does not perform type coercion, === is referred to as a strict comparison operation.

console.log(5 === '5');       // false (different types: number vs. string)
console.log(true === 1);      // false (different types: boolean vs. number)
console.log(null === undefined); // false (different types: null vs. undefined)
console.log([] === '');       // false (different types: object vs. string)
console.log([1,2] === '1,2'); // false (different types: object vs. string)

Note:
Use ‘==’ when you want to compare values for equality with type coercion.
Use ‘===’ when you want to compare values for equality without type coercion, ensuring both the value and the type are the same.
 

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