JS Practice — Built-in Objects

Proxy has trap — always true

📖 Usage Example

const p = new Proxy({}, {
  has: (target, key) => key.startsWith('a')
})
console.log('apple' in p)  // → true
console.log('banana' in p) // → false

The has trap intercepts the in operator, allowing you to control which property names are considered present on a proxy.

Proxy has trap

The has trap intercepts the in operator. When it always returns true, every key appears to exist.

Challenge: Verify that 'anything' in p is true when the has trap always returns true.

💡 Hints (1)