JS Practice — Built-in Objects

Set add() — duplicate no size increase

📖 Usage Example

const s = new Set()
s.add(1)
s.add(2)
s.add(1)   // duplicate ignored
console.log(s.size) // → 2

Use Set.add() to insert values; duplicates are silently ignored.

Set.prototype.add()

Adding a value that already exists does not increase size.

Challenge: Verify that adding a duplicate is a no-op for size.

💡 Hints (1)