Inheritance | Object-Oriented JavaScript

Prototype Chaining

Let's start with the default way of implementing inheritance—inheritance chaining through the prototype.

As you already know, every function has a prototype property, which contains an object. When this function is invoked using the new operator, an object is created and this object has a secret link to the prototype object. The secret link (called __proto__ in some environments) allows methods and properties of the prototype object to be used as if they belong to the newly-created object.

The prototype object is just a regular object and therefore it also contains a link to its prototype. And so a chain is created, called a prototype chain.

In this illustration, an object A contains a number of properties. One of the properties is the hidden __proto__ property, which points to another object, B. B's __proto__ property points to C. This chain ends with the Object object, which is the highest-level parent, and every object inherits from it.

This is all good to know, but how...

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Object-Oriented JavaScript

Object-Oriented JavaScript

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