What is the difference between null and undefined?

• undefined: the variable was declared but has no value, or a property or function result is missing. JavaScript sets it.
• null: an empty value that the programmer sets on purpose.

let a;
let b = null;
console.log(a, b);
console.log(typeof a, typeof b);
console.log(a == b, a === b);

Output:

typeof null gives "object", which is an old bug of the language.

• Previous Interview Question
• Next Interview Question

---

Tutorials
No Content Found.

Exercises & Assignments
No Content Found.

Interview Questions & Answers
No Content Found.