JS Built-ins
← Object128 / 150
ObjectisPrototypeOfbeginner

isPrototypeOf() — unrelated objects

📖 Usage Example
// Check prototype chain membership
const proto = {}
const child = Object.create(proto)
proto.isPrototypeOf(child)   // → true
Object.prototype.isPrototypeOf(child)  // → true

Use isPrototypeOf() to check whether an object exists anywhere in the prototype chain of another object.

isPrototypeOf() — returns false for unrelated objects

If the object you're testing is not in the prototype chain at all, isPrototypeOf() returns false.

Challenge: Confirm that unrelated objects return false from isPrototypeOf().

💡 Hints (1)
  • • isPrototypeOf returns false if no relationship exists