let and const

Learn to declare variables with let and const.

let and const are JavaScript's modern variable declaration keywords. They replace var.

A variable declared with let can be reassigned later. A variable declared with const cannot be reassigned; its value is fixed.

For example, you can write let age = 25 and then age = 26. But after const name = 'Alex', writing name = 'Sam' throws an error.

Which should you choose?

Using const by default is a good habit. If you know a variable will not change later, choose const; it tells the reader your intent.

If you know a variable will change, use let. For example, a counter or a loop variable is declared with let.

Avoid var in new Node.js code; it is old style and its scope is confusing.

Use const to assign name to the string 'Alex'. Use let to assign age to the number 28. Then call console.log with each.

Show example solution

const name = "Alex";
let age = 28;
console.log(name);
console.log(age);

Declare with const

____ version = "1.0.0";

Show answer

const version = "1.0.0";