Difference Between null and undefined In Javascript?

In JavaScript, null and undefined are two special values that represent the absence of a value or object. However, they are used in different contexts and have some subtle differences.

null is a value that represents the intentional absence of an object value. It can be assigned to a variable as a representation of no value.

let x = null;
console.log(x);  // Output: null

On the other hand, undefined is a value that is assigned to a variable when that variable has not been assigned a value. It can also be the value of a property of an object that does not exist.

let x;
console.log(x);  // Output: undefined

let y = {};
console.log(y.property);  // Output: undefined

It’s important to note that null and undefined are not the same thing, and they should not be used interchangeably. In JavaScript, you can use the typeof operator to determine the type of a value. For null, it returns “object”, while for undefined it returns “undefined”.

console.log(typeof null);  // Output: object
console.log(typeof undefined);  // Output: undefined

It’s also worth noting that in JavaScript, null and undefined are considered falsy values, which means that they will be evaluated as false when used in a boolean context.

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