TypeScript — Arrays

Array type syntax

// Number array
let numbers: number[] = [1, 2, 3, 4, 5];

// String array
let names: string[] = ['Alice', 'Bob', 'Charlie'];

// Using generic syntax
let scores: Array<number> = [90, 85, 88];

Readonly arrays

let readonlyArr: readonly number[] = [1, 2, 3];
// readonlyArr.push(4); // Error

Tuple arrays

let tuple: [string, number][] = [['Alice', 25], ['Bob', 30]];

Array methods

let numbers: number[] = [1, 2, 3, 4, 5];

// Map
let doubled = numbers.map(n => n * 2);

// Filter
let evens = numbers.filter(n => n % 2 === 0);

// Reduce
let sum = numbers.reduce((acc, n) => acc + n, 0);

Multi-dimensional arrays

let matrix: number[][] = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
];

Mini Practice

1. Create typed arrays
2. Use readonly arrays
3. Work with tuple arrays
4. Practice array methods

Up Next

Continue with Tuples - Tuple types.