JavaScript Prototypes

Question 1

What kind of inheritance does the JavaScript programming language use?

Answer 1

prototype-based (or prototypal) inheritance

Question 2

What is a prototype in JavaScript?

Answer 2

a JavaScript prototype is simply an object that contains properties and (predominantly) methods that can be used by other objects.

Question 3

How is it possible to call methods on strings, arrays, and numbers even though those methods don’t actually exist on objects, arrays, and numbers?

Answer 3

methods are defined on a “prototype” object and arrays simply borrow those methods when they’re needed.

Question 4

If an object does not have it’s own property or method by a given key, where does JavaScript look for it?

Answer 4

“prototype” object