undefined & null; What's the difference? #programmingmemes #codingmemes #undefined #null #coding

undefined & null; What's the difference?

If you’ve ever worked with JavaScript, you’ve probably run into a situation where a variable shows up as undefined or null, and you wondered what the difference really is.

In JavaScript, both undefined and null mean that something is missing, but they mean it in different ways. Imagine you walk into a room expecting a gift on the table. The table is there, but it’s empty. That’s undefined. The space exists, but nothing has been placed there yet. This happens when you declare a variable but don’t assign it a value.

JavaScript just shrugs and says, it’s undefined for now.

let name;

Now picture this. You do put something on the table — an empty box — and you do it on purpose. You are saying, this spot is taken, but I have cleared it out for now. That’s null. It’s not something JavaScript decides. It’s your way of saying, there’s nothing here, and that’s how I want it.

let user = null;

Here is the big idea. undefined usually means something was skipped or forgotten. It happens by accident. null means you made a clear choice to leave it empty. They might look the same, but they mean different things.

And here is a fun fact. If you check the type of null, JavaScript will tell you it is an object. That’s a bug from a long time ago that was never fixed. So now you know. When something is undefined, it is not given a value yet. When it is null, it is empty on purpose.

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[KeyframeTechSolution]

undefined & null; What's the difference?

If you’ve ever worked with JavaScript, you’ve probably run into a situation where a variable shows up as undefined or null, and you wondered what the difference really is.

In JavaScript, both undefined and null mean that something is missing, but they mean it in different ways. Imagine you walk into a room expecting a gift on the table. The table is there, but it’s empty. That’s undefined. The space exists, but nothing has been placed there yet. This happens when you declare a variable but don’t assign it a value.

JavaScript just shrugs and says, it’s undefined for now.

let name;
console.log(name); outputs => undefined

Now picture this. You do put something on the table — an empty box — and you do it on purpose. You are saying, this spot is taken, but I have cleared it out for now. That’s null. It’s not something JavaScript decides. It’s your way of saying, there’s nothing here, and that’s how I want it.

let user = null;

Here is the big idea. undefined usually means something was skipped or forgotten. It happens by accident. null means you made a clear choice to leave it empty. They might look the same, but they mean different things.

And here is a fun fact. If you check the type of null, JavaScript will tell you it is an object. That’s a bug from a long time ago that was never fixed. So now you know. When something is undefined, it is not given a value yet. When it is null, it is empty on purpose.

Subscribe for more.❤