Null vs Undefined

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Lecture 127:- Null vs Undefined

In JavaScript, null and undefined are both used to represent the absence of a value, but they are used in different contexts.

undefined is a primitive value that is automatically assigned to variables that have been declared but not initialized, or to function arguments for which no value has been passed. For example:

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let x; console.log(x); // undefined function myFunction(y) {  console.log(y); } myFunction(); // undefined

null, on the other hand, is an explicit assignment of a non-value. It represents a deliberate non-value that a programmer has assigned to a variable, property, or object. For example:

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let x = null; console.log(x); // null let person = {  firstName: "John",  lastName: "Doe",  age: null }; console.log(person.age); // null

In summary, undefined is used when a variable has not been assigned a value, whereas null is used when a value intentionally does not exist.

15. Starting with JavaScript

2 Comments

@niteshguptav63
niteshguptav63 Nov 17, 2024 at 1:39 PM

I am not able to access videos from second class and further. I have already completed first class

@niteshguptav63
niteshguptav63 Nov 16, 2024 at 10:56 AM

When will I get my course?

@admin79
admin79 Nov 17, 2024 at 1:29 PM

Now, Your query was resolved.

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