Quiz · Classes and prototypes · lesson 8 of 12Quiz — the prototype chainWhat is the prototype chain and how does property lookup use it?[A]Every object links to another object, its prototype, which has its own prototype, and so on. Reading a property checks the object first, then each prototype up this chain until the property is found or the chain ends at null, giving undefined.[B]Reading a property starts at the top of the chain, at Object.prototype, and walks down to the object, so a property defined on Object.prototype hides any property with the same name that the object itself holds.[C]Reading a property checks only the object itself; if the property is missing there, the result is undefined at once. The prototype link is used only by instanceof and never takes part in ordinary property reads or method calls.[D]When an object is created, it copies every property of its prototype into itself, so reading a property never walks a chain. Changing a method on Class.prototype later therefore has no effect on objects that were already created, since they keep their own old copies of every prototype property.Subscribe to take the courseThe course is free. Sign in with Telegram and subscribe to the channel to open every lesson.Continue with TelegramSign in another way← BackThe prototype chainNext →Exercise: bank account
