JavaScript Array Methods: Complete Guide

Why Array Methods?

Array methods make working with arrays easy. No need for loops!

Without Methods:
┌─────────────┐
│   for loop  │
│   if checks │
│   manual    │
└─────────────┘

With Methods:
┌─────────────┐
│   .map()    │
│   .filter() │
│   .reduce() │
└─────────────┘

map(): Transform Every Element

const numbers = [1, 2, 3];
const doubled = numbers.map(n => n * 2);
// [2, 4, 6]

filter(): Keep Matching Elements

const numbers = [1, 2, 3, 4, 5];
const evens = numbers.filter(n => n % 2 === 0);
// [2, 4]

reduce(): Combine to Single Value

const numbers = [1, 2, 3, 4];
const sum = numbers.reduce((acc, n) => acc + n, 0);
// 10

find(): Find First Match

const users = [{id: 1, name: 'John'}, {id: 2, name: 'Jane'}];
const user = users.find(u => u.id === 2);
// {id: 2, name: 'Jane'}

some() and every()

const ages = [18, 20, 25];
ages.some(age => age < 18);  // false
ages.every(age => age >= 18); // true

Key Takeaway

Array methods simplify array operations. map transforms, filter selects, reduce combines. Use these instead of loops for cleaner code.