How is this possible that null and undefined is not equal?

Question

Please anyone help me to this issue Why that null and undefined is not equal?

Answer 1

null and undefined are two distinct types with distinct values, and therefore not equivalent. Specifically, null is a value that signifies the intentional absence of any object value. It is assigned to a variable to indicate that it is intentionally empty, and is recognized as a special keyword in JavaScript treated as a primitive value. Conversely, undefined is a primitive value assigned to a variable when it has not been assigned any value or when a function fails to return a value. Although both null and undefined signify the absence of a value, they bear distinct connotations and thus are not considered equal to each other.

Answer 2

For example:

var x = null;
var y = undefined;

console.log(x == y); // true
console.log(x === y); // false

the first comparison x == y returns true because the double equals operator == performs type coercion, which converts null to undefined, making both variables equal. However, the second comparison x === y returns false because the triple equals operator === does not perform type coercion, and the variables have different types and values.

Answer 3

But they *are* equal,, insofar as (null == undefined) evaluates to true.

Null === undefined is false because for some reason null is an object in JS, whereas undefined is of undefined type.

Answer 4

Remember that === checks also the datatype.
Null is an object and underfined is not an object. So the expression is false.