The role of prototype in js

prototype is a property in JavaScript that points to a prototype object for shared properties and methods. Its main functions include: Inheritance: child objects inherit the prototype properties and methods of the parent object. Dynamically add properties: Dynamically add properties and methods by modifying the prototype object. Memory optimization: Multiple sub-objects share a prototype object to save memory. Code encapsulation: Encapsulate shared code into prototype objects to improve code clarity and maintainability.

The role of prototype in JavaScript

What is prototype?

Prototype is a special attribute in JavaScript that points to an object that contains properties and methods shared by other objects.

The functions of prototype

The main functions of prototype include:

• Inheritance:Child objects can inherit parent objects Properties and methods in the prototype to achieve code reuse.
• Dynamicly add properties: You can dynamically add properties and methods to sub-objects by modifying the prototype object.
• Memory optimization: Multiple sub-objects share a prototype object, which can save memory space.
• Code encapsulation: Encapsulate shared code into prototype objects to make the code clearer and easier to maintain.

Usage of prototype

You can use the following methods to access and modify the prototype object:

• Get the prototype:Object.getPrototypeOf(object)
• Set prototype: Object.setPrototypeOf(object, prototype)

Example description

The following code example demonstrates the use of prototype:

<code class="javascript">// 父对象
const Parent = {
  name: "Parent"
};

// 子对象
const Child = {
  __proto__: Parent, // 设置子对象的原型指向父对象
  age: 20
};

console.log(Child.name); // 输出: "Parent"
console.log(Child.age);  // 输出: 20

// 修改原型对象
Parent.hobby = "reading";

console.log(Child.hobby); // 输出: "reading"</code>

In this example, the Child object passes __proto__ Properties inherit the prototype of the Parent object and share its name property. At the same time, the Child object can also dynamically access and modify the properties of the parent object, such as hobby.

The above is the detailed content of The role of prototype in js. For more information, please follow other related articles on the PHP Chinese website!