JavaScript Struggles - Part 1 | Defending Variables

Defending variables in JS have its own way.

We have three ways to defend a variable let, var, const.

	Var	Let	Const
Changeable	✔	✔
Block Scope		✔	✔
Global Scope	✔
Make Arrays	✔	✔	✔

We mostly use let because of the block scope which I'll explain in the below. 👇🏻

---

Let

The keyword let makes a variable only useable within the scope it made in, you can't use it outside that scope.

E.g.

	{
	let num = 10;
	console.log(num); // Outputs: 10
	}
	console.log(num); // ERROR

view raw let-keyword.js hosted with ❤ by GitHub

---

Var

The keyword var makes a global variable, you can use it everywhere in the code.

E.g.

	{
	var num = 10;
	console.log(num); // Outputs: 10
	}
	console.log(num); // Outputs: 10

view raw var-keyword.js hosted with ❤ by GitHub

---

Const

The keyword const makes an unchangeable variable, you can't change its value.

E.g.

	const pi = 3.14159265359;
	pi = 4; // ERROR

view raw const-keyword.js hosted with ❤ by GitHub

Comments

[Abdelrahman Dwedar]

Thaks for sharing that with me, sorry for the mistake. 🙏🏻
I've heard that the block scope is taking less memory space then the general. Thanks for clearifying. 👍🏻👍🏻