Array Methods

Modern JavaScript array methods for data transformation.

Map and Filter

const numbers = [1, 2, 3, 4, 5];

// Map - transform each element
const doubled = numbers.map(n => n * 2);
console.log(doubled);  // [2, 4, 6, 8, 10]

// Filter - select elements
const evens = numbers.filter(n => n % 2 === 0);
console.log(evens);  // [2, 4]

// Chain methods
const result = numbers
  .filter(n => n > 2)
  .map(n => n ** 2);
console.log(result);  // [9, 16, 25]

Reduce

const numbers = [1, 2, 3, 4, 5];

// Sum
const sum = numbers.reduce((acc, n) => acc + n, 0);
console.log(sum);  // 15

// Object from array
const users = ['Alice', 'Bob', 'Charlie'];
const userObj = users.reduce((acc, name, i) => {
  acc[i] = name;
  return acc;
}, {});
console.log(userObj);  // {0: 'Alice', 1: 'Bob', 2: 'Charlie'}

Find and Some/Every

const users = [
  {name: 'Alice', age: 30},
  {name: 'Bob', age: 25},
  {name: 'Charlie', age: 35}
];

// Find first match
const bob = users.find(u => u.name === 'Bob');
console.log(bob);  // {name: 'Bob', age: 25}

// Check if any match
const hasYoung = users.some(u => u.age < 30);
console.log(hasYoung);  // true

// Check if all match
const allAdults = users.every(u => u.age >= 18);
console.log(allAdults);  // true