Arrays & Objects

Array Methods

These methods replace most loops in modern JavaScript. They don't change the original array; they return a new value.

Method	Returns
`map(fn)`	A new array with each item transformed
`filter(fn)`	A new array with only items that pass a test
`find(fn)`	The first item that passes, or `undefined`
`some(fn)` / `every(fn)`	`true` if any / all items pass
`reduce(fn, start)`	One value built from all items
`forEach(fn)`	Nothing; just runs `fn` for each item
`sort(fn)`	Sorts in place (changes the array)

const students = [
  { name: "Ali", marks: 85 },
  { name: "Sara", marks: 92 },
  { name: "Bilal", marks: 48 },
];

const names = students.map((s) => s.name);
const passed = students.filter((s) => s.marks >= 50);
const top = students.find((s) => s.marks > 90);
const total = students.reduce((sum, s) => sum + s.marks, 0);

console.log(names);          // ["Ali", "Sara", "Bilal"]
console.log(passed.length);  // 2
console.log(top.name);       // "Sara"
console.log(total / students.length); // 75