string / number / boolean
class
TypeScript 1.0
TypeScript's three basic primitive types. Type annotations are optional when the value is obvious (type inference).
Syntax
let name: string = "Alice";
Example
javascript
let name: string = 'Alice';
let age: number = 28;
let active: boolean = true;
let nothing: null = null;
let undef: undefined = undefined;
// Type inference (no annotation needed)
let city = 'London'; // inferred: string
let score = 95; // inferred: number
let passed = true; // inferred: boolean