search
HomeWeb Front-endJS TutorialJavascript pattern examples Observer pattern_javascript skills

There are many great people in the garden who have written these articles, but most of the examples are .NET. Today I want to give a usage example of JS. Friends who are interested can first learn about some awesome people, such as the observer section in Brother Li Huijun’s design pattern chapter
http://www.cnblogs.com/Terrylee/archive/2006/ 10/23/Observer_Pattern.html
Let me talk about my own understanding of this pattern. The core idea is: each observed object changes according to changes in the object data, and the observed object must There is the same change behavior to constrain, this constraint is the unified interface provided by the observed object to the observer. Observers develop behaviors that change data.

JS is a weakly typed script, and many things must be agreed upon. Unlike .NET, which has interface constraints, without further ado, let’s look at the example directly:
Observer instance

Copy code The code is as follows:

var ObserverObj = { /**//*Dependent object*/
FirstName : "Max",
LastName: "Gan",
Id: 1
}
var ObserverManager = { /**//*Observer*/
Observers:[], /** //*Observation object set*/
AddObserver: function(item){/**//*Add observation object*/
this.Observers.push(item);
},
Change: function(obj){ /**//*Change object behavior*/
for(var item in obj){
ObserverObj[item] = obj[item];
}//Change the data dependent object data
for(var i = 0,len = this.Observers.length; i var item = this.Observers[i];
item.Display(); //After the object changes, change the observation object The behavior of Display; is a unified interface
}
}
}
var Header = function(){ /**//*Observation object Header*/
this.Display = function(){
alert(ObserverObj.FirstName);
}
}
var Content = function(){ /**//*Observe object Content*/
this.Display = function(){
alert (ObserverObj.LastName);
}
}
var Foot = function(){ /**//*Observation object Foot*/
this.Display = function(){
alert(ObserverObj. Id);
}
}

The above example ObserverManager only provides the binding method (AddObserver). There are other coding techniques such as unbinding. Maybe everyone Just think about it and you will know. In fact, the ultimate purpose of these codes is that when the Observers data is changed, other objects will respond accordingly according to the data changes. OK, now let's bind them.
Copy code The code is as follows:

/***Bind observer action***/
ObserverManager .AddObserver(new Header());
ObserverManager.AddObserver(new Content());
ObserverManager.AddObserver(new Foot());

How will we use it in the end? Woolen cloth? (An imbecile question... haha) Look at the example.
How to use
Copy the code The code is as follows:

I attach the entire example Now, friends who are interested can download it and take a look.
Javascript Observer Mode.rar
How far a person can go depends on who he travels with
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
JavaScript in Action: Real-World Examples and ProjectsJavaScript in Action: Real-World Examples and ProjectsApr 19, 2025 am 12:13 AM

JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.

JavaScript and the Web: Core Functionality and Use CasesJavaScript and the Web: Core Functionality and Use CasesApr 18, 2025 am 12:19 AM

The main uses of JavaScript in web development include client interaction, form verification and asynchronous communication. 1) Dynamic content update and user interaction through DOM operations; 2) Client verification is carried out before the user submits data to improve the user experience; 3) Refreshless communication with the server is achieved through AJAX technology.

Understanding the JavaScript Engine: Implementation DetailsUnderstanding the JavaScript Engine: Implementation DetailsApr 17, 2025 am 12:05 AM

Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.

Python vs. JavaScript: The Learning Curve and Ease of UsePython vs. JavaScript: The Learning Curve and Ease of UseApr 16, 2025 am 12:12 AM

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python vs. JavaScript: Community, Libraries, and ResourcesPython vs. JavaScript: Community, Libraries, and ResourcesApr 15, 2025 am 12:16 AM

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

From C/C   to JavaScript: How It All WorksFrom C/C to JavaScript: How It All WorksApr 14, 2025 am 12:05 AM

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

JavaScript Engines: Comparing ImplementationsJavaScript Engines: Comparing ImplementationsApr 13, 2025 am 12:05 AM

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

Beyond the Browser: JavaScript in the Real WorldBeyond the Browser: JavaScript in the Real WorldApr 12, 2025 am 12:06 AM

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.

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

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Tools

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.