Lesson 4 +10 XP

Primitive Types in TypeScript

Primitive Types

TypeScript supports JavaScript's primitive types: number, string, boolean, symbol, and bigint.

Overview of Primitives

Type	Examples	Description
`number`	`42`, `3.14`, `0xFF`	Floating point numbers and integers.
`string`	`"hello"`, `'world'`, `` sum: ${x} ``	Textual data and template literals.
`boolean`	`true`, `false`	Logical truth values.
`bigint`	`100n`, `BigInt(9007199254740991)`	Arbitrarily large integers.
`symbol`	`Symbol("id")`	Unique and immutable primitive values.

Array & Tuple Primitives

Arrays can be typed using array syntax type[] or Array<type>.

let scores: number[] = [90, 85, 95];
let names: Array<string> = ["Alice", "Bob"];

// Tuple: fixed-length array with specified types at each position
let tuple: [string, number] = ["Alice", 25];

TL;DR

Always use lowercase primitive type names (number, string, boolean), not upper-cased wrappers (Number, String).
Tuples define fixed-length arrays with distinct element types at each index.