Introduction to proxy pattern in JavaScript design patterns
This article mainly introduces the proxy mode of JavaScript design pattern, briefly describes the concept, function, and composition of the proxy mode, and combines the example form with a more detailed analysis of the definition and use of the JavaScript proxy mode. Friends who need it You can refer to the following
This article explains the proxy pattern of JavaScript design patterns with examples. Share it with everyone for your reference. The details are as follows:
1. The concept of agency model
Agency, as the name suggests, is to help others do things. GoF defines the agency model as follows:
Agency Mode (Proxy) provides a proxy for other objects to control access to this object. The proxy pattern enables proxy objects to control references to specific objects. A proxy can be almost any object: a file, a resource, an object in memory, or something difficult to copy.
Explanation: A housing agency can help the seller sell the house to the buyer. During this period, the seller can set the price at which he wants to sell the house, and the buyer can also propose the type of house he wants to buy. An intermediary can help with the intermediate steps. Finally a deal is concluded. An intermediary can act as an agent for many house sales and rentals at the same time.
Composition of the proxy pattern:
Abstract role: Business methods implemented by declaring real roles through interfaces or abstract classes.
Agent role: implements an abstract role and is an agent of the real role. It implements the abstract method through the business logic method of the real role and can attach its own operations.
Real role: implement abstract role, define the business logic to be implemented by the real role, and be called by the agent role.
2. The functions and precautions of the proxy mode
Mode functions:
1.Remote proxy (an object locally proxies objects in different spaces)
2. Virtual agent (create expensive objects as needed, such as rendering web pages and temporarily use placeholders instead of real images)
3. Security agent (control the access rights of confirmed objects)
4. Intelligent guidance (calling the object agent to handle other things such as garbage collection mechanism)
Notes:
1. Don’t abuse the agent, sometimes it just adds complexity to the code
3. Agent mode code and practical summary
<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title>代理模式</title> </head> <body> <script> //代理模式需要三方 //1.买家 function maijia(){ this.name = "小明"; this.money = "30万"; } //2.中介 function zhongjie(){ } zhongjie.prototype.maifang = function(){ //new fongdong(new maijia()).maifang("20万"); new fongdong(new maijia()).maifang("20万"); } //3.卖家 function fongdong(maijia){ this.maijia_name = maijia.name; this.maijia_money = maijia.money; this.maifang = function(money){ // console.log("收到了来自【"+this.maijia_name+"】"+money+"人民币"); console.log("收到了来自【"+this.maijia_name+"】"+this.maijia_money+"人民币"); } } (new zhongjie()).maifang(); </script> <script> // A2B function A(){ this.money = "20RMB"; } function to(){ if(!(this instanceof to)){ return new to; } } to.prototype.maifang = function(){ var a = new A(); new B().maifang(a.money); } function B(){ this.maifang = function(money){ console.log("收到了钱"+money); } } (new to()).maifang(); to().maifang(); </script> </body> </html>
The operation effect is as follows:
and above That’s the entire content of this article. I hope it will be helpful to everyone’s study. For more related content, please pay attention to the PHP Chinese website!
Related recommendations:
About the use of RegExp objects and brackets in JS regular expressions
jQuery prevents event bubbling Case Analysis
The above is the detailed content of Introduction to proxy pattern in JavaScript design patterns. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

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

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

In the Java framework, the difference between design patterns and architectural patterns is that design patterns define abstract solutions to common problems in software design, focusing on the interaction between classes and objects, such as factory patterns. Architectural patterns define the relationship between system structures and modules, focusing on the organization and interaction of system components, such as layered architecture.

The decorator pattern is a structural design pattern that allows dynamic addition of object functionality without modifying the original class. It is implemented through the collaboration of abstract components, concrete components, abstract decorators and concrete decorators, and can flexibly expand class functions to meet changing needs. In this example, milk and mocha decorators are added to Espresso for a total price of $2.29, demonstrating the power of the decorator pattern in dynamically modifying the behavior of objects.

1. Factory pattern: Separate object creation and business logic, and create objects of specified types through factory classes. 2. Observer pattern: allows subject objects to notify observer objects of their state changes, achieving loose coupling and observer pattern.

Design patterns solve code maintenance challenges by providing reusable and extensible solutions: Observer Pattern: Allows objects to subscribe to events and receive notifications when they occur. Factory Pattern: Provides a centralized way to create objects without relying on concrete classes. Singleton pattern: ensures that a class has only one instance, which is used to create globally accessible objects.

The Adapter pattern is a structural design pattern that allows incompatible objects to work together. It converts one interface into another so that the objects can interact smoothly. The object adapter implements the adapter pattern by creating an adapter object containing the adapted object and implementing the target interface. In a practical case, through the adapter mode, the client (such as MediaPlayer) can play advanced format media (such as VLC), although it itself only supports ordinary media formats (such as MP3).

TDD is used to write high-quality PHP code. The steps include: writing test cases, describing the expected functionality and making them fail. Write code so that only the test cases pass without excessive optimization or detailed design. After the test cases pass, optimize and refactor the code to improve readability, maintainability, and scalability.

The Guice framework applies a number of design patterns, including: Singleton pattern: ensuring that a class has only one instance through the @Singleton annotation. Factory method pattern: Create a factory method through the @Provides annotation and obtain the object instance during dependency injection. Strategy mode: Encapsulate the algorithm into different strategy classes and specify the specific strategy through the @Named annotation.

The advantages of using design patterns in Java frameworks include: enhanced code readability, maintainability, and scalability. Disadvantages include complexity, performance overhead, and steep learning curve due to overuse. Practical case: Proxy mode is used to lazy load objects. Use design patterns wisely to take advantage of their advantages and minimize their disadvantages.
