Variables and Data Types

JavaScript in Node.js supports let, const, and (legacy) var.

JavaScript

const name = 'Kodstigen';   // cannot be reassigned
let xp = 0;                 // can be reassigned
xp += 10;

console.log(name, 'has', xp, 'XP');
console.log('typeof name:', typeof name);

const name = 'Kodstigen';   // cannot be reassigned
let xp = 0;                 // can be reassigned
xp += 10;

console.log(name, 'has', xp, 'XP');
console.log('typeof name:', typeof name);

Core types

Type	Example
string	`'hello'`
number	`42`, `3.14`
boolean	`true`
object	`{ id: 1 }`
array	`[1, 2, 3]`
null / undefined	absence of value

Prefer const by default; use let only when you need to reassign.

Variables and Data Types

Core types

📝 Variables Quiz