What is null in Javascript

It is commonly used as a placeholder or to indicate that a variable currently has no value or is empty. Assigning `null` to a variable means it does not hold any value at the moment.

Here's an example:

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

In the above code, myVariable is assigned the value null, indicating that it currently does not have any value assigned to it.

What is the difference between undefined and null in JavaScript?

In JavaScript, undefined and null both represent the absence of a value, but they are used in different situations. undefined typically means a variable has been declared but not assigned a value, while null is explicitly assigned to indicate the intentional absence of any value or object.

undefined is a primitive value automatically assigned to a variable that has been declared but not assigned a value. It is also the default return value of a function that does not explicitly return a value, indicating that the variable has been declared but has no assigned value.

let x; // variable is declared but not assigned a value
console.log(x); // Output: undefined

function doSomething() {
  // No return statement
}

console.log(doSomething()); // Output: undefined

null, on the other hand, is an assignment value that represents the intentional absence of any object value. It is explicitly assigned to a variable to indicate that it is intentionally empty.

let y = null; // variable is assigned the value of null
console.log(y); // Output: null

In summary, undefined is used when a variable has been declared but has no assigned value, while null is used to indicate the intentional absence of any object value.