JavaScript null

What is null?

In JavaScript, null means:

• Intentional absence of any value.
• It is a primitive value that represents "nothing" or "empty"

Developers assign null when they want to say that a variable should have no value.

How to Use null

You assign null manually:

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

null is explicitly set by the programmer to indicate "no value".

Examples and Outputs

Example 1: Setting null

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

Example 2: Before and After Assignment

let city = null;
console.log(city); // Output: null
city =
"Paris";
console.log(city); // Output: Paris

Here:

• Initially, city has no value (null).
• Later, a value is assigned.

Type of null

Interestingly, typeof null returns "object" (this is a historical bug in JavaScript that was never fixed).

Example:

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

Even though typeof null is "object" , null is NOT an object — it's a primitive value.

Difference Between undefined and null

Example Comparison

let a;
let b = null;
console.log(a); // Output: undefined
console.log(b); // Output: null
console.log(typeof a); // Output: "undefined"
console.log(typeof b); // Output: "object"

Null in Conditional Statements

In conditions, null behaves like false (it’s falsy).

Example:

let user = null;
if (user) {
console.log("User exists");
} else {
console.log("No user");
}
// Output: No user

null is treated as false in logical expressions.

Checking for null

You can check if a variable is null:

let data = null;
if (data === null) {
console.log("Data is null");
}
// Output: Data is null

Use === (strict equality) to properly check for null without type conversion.