Object-Oriented JavaScript — Inheritance

Object-Oriented JavaScript — Inheritance

There’re various ways to do inheritance with JavaScript.

Prototype Chaining

An object has a prototype chain.

The inherit properties from them.

For instance, we can create a chain of constructors by writing:

function Shape() {}
Shape.prototype.name = 'Shape';
Shape.prototype.toString = function() {
  return this.name;
};
function Square() {}
Square.prototype = new Shape();
Square.prototype.constructor = Square;
Square.prototype.name = 'Square';

We have the Shape constructor with some prototype properties.

Then we created a Square constructor with the prototype set to the Shape constructor.

Then we set the constructor to the Square to make instanceof sqaure returns true if we use instanceof with a Square instance.

If we want to call the parent constructor within the child constructor to populate its properties, we can change the code.

We can write:

function Shape(name) {
  this.name = name;
}
Shape.prototype.toString = function() {
  return this.name;
};
function Square(name, length) {
  Shape.call(this, name);
  this.length = length
}
Square.prototype = Object.create(Shape.prototype);
Square.prototype.constructor = Square;

to create the Shape constructor with the name property.

Then we have the Square property with the name and length parameters.

We call the Shape constructor with call and we set the first argument to this so it’s called with the Square constructor as this .

name is what we pass into the Shape constructor.

To create the prototype, we call Object.create to inherit the properties from Shape.prototype .

And we set the constructor the same way so that instanceof still reports correctly.z

programming technology javascript

Bootstrap 5 Complete Course with Examples

Bootstrap 5 Tutorial - Bootstrap 5 Crash Course for Beginners

Nest.JS Tutorial for Beginners

Hello Vue 3: A First Look at Vue 3 and the Composition API

Building a simple Applications with Vue 3

Deno Crash Course: Explore Deno and Create a full REST API with Deno

How to Build a Real-time Chat App with Deno and WebSockets

Convert HTML to Markdown Online

HTML entity encoder decoder Online

JavaScript: Chessboard Program

Exercise from Eloquent JavaScript. Today, we will write a function that forms a chessboard. You can find the exercise in the Eloquent Javascript book (3rd edition, chapter 2; Program Structure). Write a program that creates a string that represents an 8×8 grid, using newline characters to separate lines. At each position of the grid there is either a space or a “#” character. The characters should form a chessboard.

Learning JavaScript: Development Environments for JavaScript Programming

One of the nice things about learning JavaScript these days is that there is a plethora of choices for writing and running JavaScript code. In this article, I’m going to describe a few of these environments and show you the environment I’ll be using in this series of articles.

Learning JavaScript: Data Types and Variables

To paraphrase the title of an old computer science textbook, “Algorithms + Data = Programs.” The first step in learning a programming language such as JavaScript is to learn what types of data the language can work with. The second step is to learn how to store that data in variables. In this article I’ll discuss the different types of data you can work with in a JavaScript program and how to create and use variables to store and manipulate that data.

[ Professor JavaScript ]: Introduction

Professor JavaScript is a JavaScript online learning courses YouTube Channel. Students can learn how to develop codes with JavaScript from basic to advanced levels through the online courses in this YouTube channel.

Introduction to JavaScript Async Programming

Async callbacks or promises. Introduction to JavaScript Async Programming