JavaScript Set and Map

Set: Unique Values

Set stores unique values. No duplicates allowed.

```javascript const numbers = new Set([1, 2, 3, 3, 4]); console.log(numbers); // Set {1, 2, 3, 4}

numbers.add(5); numbers.has(3); // true numbers.delete(2); ```

**Use when:** You need unique values

Map: Key-Value Pairs

Map is like object but with any key type.

```javascript const map = new Map(); map.set('name', 'John'); map.set(1, 'One'); map.set(true, 'Yes');

map.get('name'); // "John" map.has('name'); // true ```

**Use when:** You need keys that aren't strings

Key Takeaway

Set stores unique values. Map stores key-value pairs with any key type. Use when arrays/objects aren't enough.