Mastering JavaScript Design Patterns

Monkey patching

We've seen a number of methods of creating fake objects in JavaScript. When creating the spy, we made use of a method called monkey patching. Monkey patching allows you to dynamically change the behavior of an object by replacing its functions. We can use this sort of approach without having to revert to full fake objects. Any existing object can have its behavior changed in isolation using this approach. This includes built-in objects such as strings and arrays.