search
HomeWeb Front-endFront-end Q&AHow to implement inheritance in javascript? A brief analysis of various methods

Before talking about JavaScript inheritance, we need to first understand what a class is. In common programming languages, such as Java, C, C#, etc., a class is a program structure used to encapsulate data and methods. Objects can be created through instantiation to achieve code reuse and abstraction.

But in JavaScript, classes are defined and used slightly differently than in other languages. JavaScript classes are based on objects, and objects are at the center of the language. JavaScript does not have such a complicated class inheritance system, and all classes can be inherited. That is to say, except for some specific built-in objects, such as Math, Date, etc., most objects in JavaScript can serve as base classes.

In JavaScript, inheritance has the following methods:

  1. Prototype chain inheritance:

Prototype chain inheritance is the most basic inheritance method in JavaScript. Use prototypes to implement function and property inheritance from parent classes. Simply put, the prototype of the subclass points to the instance of the parent class, thereby achieving inheritance. In this way, you can extend the parent class and add new attributes and methods.

For example:

function Animal() {
  this.species = "动物";
}

function Cat(name, color) {
  this.name = name;
  this.color = color;
}

Cat.prototype = new Animal();  // 将 Cat 的原型对象指向 Animal 的实例

var cat1 = new Cat('小红', '黑色');
console.log(cat1.species);  // 输出 "动物"
  1. Borrowed constructor inheritance:

Borrowed constructor inheritance, also called classic inheritance or stolen constructor inheritance, refers to the Inheritance is achieved by calling the constructor of the parent class in the constructor of the subclass. This method is different from prototype chain inheritance. It can inherit the attributes of the parent class and achieve attribute independence.

For example:

function Animal(name, color) {
  this.name = name;
  this.color = color;
}

function Cat(name, color) {
  Animal.call(this, name, color);  // 在 Cat 类的构造函数中调用 Animal 类的构造函数
}

var cat1 = new Cat('小红', '黑色');
console.log(cat1.name);   // 输出 "小红"
console.log(cat1.color);  // 输出 "黑色"
  1. Combined inheritance:

Combined inheritance refers to combining prototype chain inheritance and borrowed constructor inheritance, so that At the same time, it inherits the properties and methods of the parent class, and can use the properties and methods of the parent class.

For example:

function Animal(name, color) {
  this.name = name;
  this.color = color;
}

Animal.prototype.eat = function() {
  console.log('我是一只动物,我可以吃东西!');
}

function Cat(name, color) {
  Animal.call(this, name, color);
}

Cat.prototype = new Animal();
Cat.prototype.constructor = Cat;

var cat1 = new Cat('小红', '黑色');
console.log(cat1.name);   // 输出 "小红"
console.log(cat1.color);  // 输出 "黑色"
cat1.eat();              // 输出 "我是一只动物,我可以吃东西!"
  1. Parasitic inheritance:

Parasitic inheritance refers to creating a function that is only used to encapsulate the inheritance process. In this function Enhance the object in some way and finally return this object. This object can be used as a prototype object for subclasses to achieve inheritance.

For example:

function Animal(name) {
  var obj = {
    name: name,
    eat: function() {
      console.log('我是一只动物,我可以吃东西!');
    }
  };
  return obj;
}

function Cat(name, color) {
  var animal = Animal.call(this, name);
  animal.color = color;
  return animal;
}

var cat1 = new Cat('小红', '黑色');
console.log(cat1.name);   // 输出 "小红"
console.log(cat1.color);  // 输出 "黑色"
cat1.eat();              // 输出 "我是一只动物,我可以吃东西!"
  1. Parasitic combination inheritance:

Parasitic combination inheritance refers to parasitic inheritance based on combination inheritance. Optimize object inheritance performance. Inheritance can be achieved by creating a new object that inherits the prototype of the parent class, avoiding the pitfalls of initializing the object when calling the parent class constructor.

For example:

function Animal(name) {
  this.name = name;
}

Animal.prototype.eat = function() {
  console.log('我是一只动物,我可以吃东西!');
};

function Cat(name, color) {
  Animal.call(this, name);
  this.color = color;
}

Cat.prototype = Object.create(Animal.prototype);
Cat.prototype.constructor = Cat;

var cat1 = new Cat('小红', '黑色');
console.log(cat1.name);   // 输出 "小红"
console.log(cat1.color);  // 输出 "黑色"
cat1.eat();              // 输出 "我是一只动物,我可以吃东西!"

In summary, JavaScript inheritance can be implemented in a variety of ways. In actual development, you need to choose the appropriate method according to specific scenarios and needs.

The above is the detailed content of How to implement inheritance in javascript? A brief analysis of various methods. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
HTML and React's Integration: A Practical GuideHTML and React's Integration: A Practical GuideApr 21, 2025 am 12:16 AM

HTML and React can be seamlessly integrated through JSX to build an efficient user interface. 1) Embed HTML elements using JSX, 2) Optimize rendering performance using virtual DOM, 3) Manage and render HTML structures through componentization. This integration method is not only intuitive, but also improves application performance.

React and HTML: Rendering Data and Handling EventsReact and HTML: Rendering Data and Handling EventsApr 20, 2025 am 12:21 AM

React efficiently renders data through state and props, and handles user events through the synthesis event system. 1) Use useState to manage state, such as the counter example. 2) Event processing is implemented by adding functions in JSX, such as button clicks. 3) The key attribute is required to render the list, such as the TodoList component. 4) For form processing, useState and e.preventDefault(), such as Form components.

The Backend Connection: How React Interacts with ServersThe Backend Connection: How React Interacts with ServersApr 20, 2025 am 12:19 AM

React interacts with the server through HTTP requests to obtain, send, update and delete data. 1) User operation triggers events, 2) Initiate HTTP requests, 3) Process server responses, 4) Update component status and re-render.

React: Focusing on the User Interface (Frontend)React: Focusing on the User Interface (Frontend)Apr 20, 2025 am 12:18 AM

React is a JavaScript library for building user interfaces that improves efficiency through component development and virtual DOM. 1. Components and JSX: Use JSX syntax to define components to enhance code intuitiveness and quality. 2. Virtual DOM and Rendering: Optimize rendering performance through virtual DOM and diff algorithms. 3. State management and Hooks: Hooks such as useState and useEffect simplify state management and side effects handling. 4. Example of usage: From basic forms to advanced global state management, use the ContextAPI. 5. Common errors and debugging: Avoid improper state management and component update problems, and use ReactDevTools to debug. 6. Performance optimization and optimality

React's Role: Frontend or Backend? Clarifying the DistinctionReact's Role: Frontend or Backend? Clarifying the DistinctionApr 20, 2025 am 12:15 AM

Reactisafrontendlibrary,focusedonbuildinguserinterfaces.ItmanagesUIstateandupdatesefficientlyusingavirtualDOM,andinteractswithbackendservicesviaAPIsfordatahandling,butdoesnotprocessorstoredataitself.

React in the HTML: Building Interactive User InterfacesReact in the HTML: Building Interactive User InterfacesApr 20, 2025 am 12:05 AM

React can be embedded in HTML to enhance or completely rewrite traditional HTML pages. 1) The basic steps to using React include adding a root div in HTML and rendering the React component via ReactDOM.render(). 2) More advanced applications include using useState to manage state and implement complex UI interactions such as counters and to-do lists. 3) Optimization and best practices include code segmentation, lazy loading and using React.memo and useMemo to improve performance. Through these methods, developers can leverage the power of React to build dynamic and responsive user interfaces.

React: The Foundation for Modern Frontend DevelopmentReact: The Foundation for Modern Frontend DevelopmentApr 19, 2025 am 12:23 AM

React is a JavaScript library for building modern front-end applications. 1. It uses componentized and virtual DOM to optimize performance. 2. Components use JSX to define, state and attributes to manage data. 3. Hooks simplify life cycle management. 4. Use ContextAPI to manage global status. 5. Common errors require debugging status updates and life cycles. 6. Optimization techniques include Memoization, code splitting and virtual scrolling.

The Future of React: Trends and Innovations in Web DevelopmentThe Future of React: Trends and Innovations in Web DevelopmentApr 19, 2025 am 12:22 AM

React's future will focus on the ultimate in component development, performance optimization and deep integration with other technology stacks. 1) React will further simplify the creation and management of components and promote the ultimate in component development. 2) Performance optimization will become the focus, especially in large applications. 3) React will be deeply integrated with technologies such as GraphQL and TypeScript to improve the development experience.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools