JS Practice — Built-in Objects

Map set() — size after set

📖 Usage Example

const m = new Map()
m.set('a', 1)
m.set('b', 2)
console.log(m.size) // → 2

Use Map.set() to add or update a key-value pair; it returns the map itself.

Map.prototype.set()

Each unique key added increases size by 1.

Challenge: Verify that size equals the number of unique keys set.

💡 Hints (1)