JS Practice — Built-in Objects

Interface — Implement a Stack

📖 Usage Example

function createStack<T>() {
  const items: T[] = []
  return {
    push: (x: T) => items.push(x),
    pop: () => items.pop(),
  }
}

Closures can implement interfaces without classes — returning an object with typed method signatures.

Interfaces as Contracts: Stack

Challenge: Implement createStack<T>() returning an object satisfying the Stack<T> interface.

const s = createStack<number>()
s.push(1); s.push(2)
s.pop()   // → 2
s.peek()  // → 1
s.size    // → 1

💡 Hints (1)