Vue 3: Full functional analysis, a magical journey to explore the new front-end continent!

This paper aims to study and analyze the functional implementation of Vue 3, and deeply explore the characteristics and innovations of Vue 3 as the next-generation front-end development framework. The paper first introduces the background and development history of Vue 3, and then focuses on the core functions and improvements it introduced, including comprehensive reconstruction of the responsive system, Composition API, performance optimization, TypeScript support, etc. Finally, the paper also verifies the effect of Vue 3 in actual project applications through examples and case analysis. Research results show that the functional implementation of Vue 3 can not only greatly improve development efficiency and code maintainability, but also provide better performance and a richer development experience.

Article directory

1 Background and development history of Vue 3
- 1.1 Vue’s past and present life
- 1.2 The birth background and motivation of Vue 3
2 Core functions and improvements of Vue 3
3 Practical application cases and effect verification of Vue 3
- 3.1 Example Analysis: Use Vue 3 to develop a simple real-time chat application
- 3.2 Case Study: Applying the performance optimization function of Vue 3 in large-scale enterprise-level projects

1 Background and development history of Vue 3

1.1 Vue’s past and present life

Vue is a popular JavaScript framework for building user interfaces. It was developed by You Yuxi in 2014 and released in the same year. Vue is designed to be simple, flexible, and extensible, and can be used to build single-page applications (SPA) and complex front-end applications.

The origins of Vue can be traced back to You Yuxi’s experience in developing other frameworks. Prior to this, he participated in the development of a framework called AngularJS. However, Yuxi You was dissatisfied with some of AngularJS's decisions, especially its complexity and learning curve. So he started thinking about how to create a simpler, more lightweight framework.

After a period of thinking, You Yuxi began to develop his own framework and released the first version of Vue in 2014. Vue is designed to make it easier for developers to build user interfaces by providing simple yet powerful tools. It uses a component-based architecture that allows developers to break the UI into reusable components and combine these components in a declarative manner.

Over time, Vue has gained more and more attention and usage. Its simplicity and flexibility make it one of the preferred frameworks for many developers and businesses. Vue's community is also growing rapidly, providing developers with a wealth of resources and support.

In recent years, as front-end technology continues to develop and the complexity of front-end applications increases, Vue has also continued to evolve. The release of Vue 2 brings better performance and more features. At the same time, Vue continues to roll out new versions to improve performance, add functionality, and resolve issues in previous versions. Vue 3 is the latest major version and brings some major improvements such as better static typing support and better TypeScript integration.

Overall, Vue, as a modern JavaScript framework, has won the favor of more and more developers through its simplicity, flexibility, and scalability. Its predecessor can be traced back to You Yuxi

1.2 The birth background and motivation of Vue 3

The background and motivation of Vue 3 can be explained from the following aspects:

Refactoring of the responsive system: One of the core features of Vue.js is the responsive system, which allows developers to easily handle data changes and automatically reflect the changes to the application's views. However, the Vue 2.x version of the responsive system has some limitations, such as the inability to detect changes in dynamic properties of arrays and objects. Vue 3 reconstructs the responsive system and introduces the Proxy API, which solves these limitations and provides more powerful and flexible responsive capabilities.
Better performance: Vue 3 has been optimized in terms of performance, using an optimized virtual DOM algorithm (Fragments), reducing memory overhead during rendering, and supporting local updates based on changed parts, thus improving the performance of the application. Rendering performance.
Better TypeScript support: Vue 3 fully supports TypeScript. Through TypeScript's type checking and code prompts, developers can detect potential errors earlier and provide a better development experience.
Less package size: Vue 3 introduces static tags that can be analyzed at compile time, thereby eliminating some runtime code in the Vue 2.x version, reducing the package size and improving application performance.
Better development experience: Vue 3 provides some new development tools and APIs, such as Composition API, which makes component logic easier to test and reuse. It also adds some new debugging tools, such as Devtools, thus providing better development experience.

The background and motivation of Vue 3 is mainly to provide better responsiveness, performance optimization, TypeScript support, package size reduction and a better development experience.

2 Core functions and improvements of Vue 3

2.1 Comprehensive reconstruction of responsive system

Vue 3 has completely restructured the responsive system, mainly by using Proxy to replace the Object.defineProperty used in Vue 2.x to achieve more efficient and comprehensive responsive capabilities. Here are some important improvements to the Vue 3 reactive system:

Use Proxy instead of Object.defineProperty: Vue 2.x uses Object.defineProperty to intercept the reading and modification of data, and implement responsiveness by recursively traversing object properties. However, this approach has some limitations and performance issues. Vue 3 introduces Proxy, which can intercept object operations in a more direct and flexible way, providing better performance and more comprehensive responsive support.
Lazy recursion and caching: The Vue 3 reactive system uses a lazy recursion strategy when tracking dependencies. It delays dependency tracking and collects dependencies only when actually needed. This strategy reduces unnecessary calculations and updates and improves performance. At the same time, Vue 3 also optimizes the dependent caching mechanism to avoid repeated tracking and updates.
Improvements in nested data: Vue 3’s reactive system better supports the reactivity of nested objects and arrays. It correctly performs dependency tracking and updates in nested objects, solving some of the limitations of Vue 2.x in this regard.
Optional weak mappings: Vue 3’s reactive system allows developers to create optional weak mappings by marking some properties as “non-tracking”. Such properties are not tracked as dependencies, which is useful for large data structures or properties that need to change frequently but don't need to be reactive.

These refactorings and improvements make Vue 3's responsive system more efficient, flexible, and comprehensive. It can capture data operations more accurately, automatically track dependencies, and keep views and data updated synchronously. At the same time, it also provides better performance and better support for nested data, making Vue 3 significantly improved in performance and development experience.

2.2 Composition API

Composition API is a new way of writing component logic introduced in Vue 3. It is a function-based API designed to solve some limitations and challenges of component logic reuse and code organization in Vue 2.x.

By using the Composition API, the relevant logic of components can be organized together and presented in a more intuitive and readable way. Compared with the optional API in Vue 2.x, the Composition API provides more flexibility and readability.

Here are some features and benefits of the Composition API:

Function organization: By using the Composition API, functions can be used to organize and encapsulate the logic of components. Each function can focus on just one specific functionality or behavior, which makes the code more readable, maintainable, and supports better code reuse.
Logic encapsulation: Use the Composition API to better encapsulate and share component logic. A set of related functional logic can be encapsulated in a function and reused when needed. This helps reduce redundant code and improve code reuse.
Composition functions: The Composition API allows multiple logic to be combined together to form more complex functions. By decomposing component logic into small composable functions, these functions can be more flexibly combined and reused to build more complex functionality.
Better TypeScript support: Composition API has better support for TypeScript and can provide more accurate type deduction and code hints. TypeScript can better understand the types of function parameters and return values, making the development process more reliable and efficient.
Better code organization: The Composition API provides a more intuitive way to organize component code. By decomposing logic into functions, the responsibilities of each function can be more clearly demarcated, making the code easier to maintain and extend.

The Composition API provides a more flexible, readable, and better-organized way to write component logic. It is an important improvement in Vue 3 and is a powerful tool for developers to build complex components and improve code reusability.

2.3 Performance optimization

Performance optimization is a very important aspect in application development, which aims to improve the response speed, resource utilization and user experience of the application. Here are some common performance optimization tips:

Reduce network requests: Reducing the number of network requests required to load a page can significantly improve page loading speed. You can reduce the number of requests by merging, compressing and caching static resources, using lazy loading and on-demand loading.
Optimize images and multimedia resources: Images and multimedia resources are often the bottleneck for page loading speed. Optimizing the size and format of these resources, using appropriate compression and scaling, can reduce load times and improve user experience.
Use caching mechanism: Proper use of browser cache, CDN cache and server-side cache can reduce the number of requests to the server and speed up page loading.
Delayed loading and lazy loading: Delay loading or lazy loading of some content on the page that is not immediately visible or unimportant to reduce the initial loading time and required resources of the page.
Code optimization: Optimize JavaScript code, including reducing unnecessary repeated calculations, optimizing loops and recursions, using throttling and anti-shake functions to control event triggering frequency and reduce resource consumption.
Use virtual lists and virtual scrolling: For lists with large amounts of data or scrolling areas with long content, using virtual lists and virtual scrolling technology can reduce the number of DOM elements and improve rendering performance.
Avoid forced synchronization of layout: Avoid frequently modifying DOM elements and trigger layout reflow, which can reduce the cost of page redrawing and reflow. Use CSS3 animations and transitions instead of JavaScript to achieve animation effects.
Build using production environment: Use compressed and obfuscated code in production environment, turn off debugging information and warnings in developer tools, and reduce the size of resource files.
Performance monitoring and analysis: Use browser developer tools, performance analysis tools, and monitoring tools to perform performance analysis and testing on applications to identify performance bottlenecks and optimize them.

The above are some common performance optimization techniques. There are other optimization strategies to choose from based on specific development scenarios and needs. It is worth noting that performance optimization is an ongoing process that requires continuous testing, analysis, and adjustments during the development process to achieve the best performance results.

2.4 TypeScript support

Vue 3 has significantly improved TypeScript support, allowing for better type deduction and type checking when developing Vue applications using TypeScript.

Here are some improvements in Vue 3’s support for TypeScript:

Type inference: Vue 3 uses a more powerful type inference algorithm, which can accurately deduce the data type, property type and event type in the component. This allows developers to get good type checking without explicitly specifying types.
Transparent state type: Vue 3 improves the type derivation of responsive state and can automatically deduce the type of state. This means that when using reactive data in a component, the type of the data can be accurately obtained and type checked.
TSX support: Vue 3's support for TSX has also been enhanced, allowing for better type checking and code hints when writing components using JSX or TSX.
Composition API type support: The Composition API in Vue 3 provides better TypeScript support. Through the Composition API, you can better define the parameter types and return value types of functions and get accurate type checking.
Improved error prompts: Vue 3 has also improved type-related error prompts, which can indicate the location and cause of type errors in more detail and accurately, helping developers find and fix problems faster.

In addition to the above improvements, Vue 3 also provides some TypeScript-related tools and auxiliary functions, such as defineProps, defineEmits and withDefaults, etc., to better define the properties, events and default values of components and perform type checking.

Vue 3's support for TypeScript has been significantly improved, allowing for better type derivation, type checking, and error prompts when developing Vue applications using TypeScript. This improves development efficiency, reduces potential type-related problems, and makes code more reliable and easier to maintain.

2.5 Other functional improvements

In addition to improvements to the Composition API and TypeScript support, Vue 3 has many other feature improvements. Here are some important feature improvements:

Faster rendering performance: Vue 3 is optimized for rendering performance, using a new compiler and runtime module that reduces the size of generated code and improves execution efficiency.
Smaller package size: Vue 3 introduces Tree-shaking support, which can better optimize the built package size. This means that only the code you use will be included in the final build, reducing application load times.
Better recursive component support: Vue 3 has made improvements in recursive components, can better support infinitely nested component structures, and has lower memory consumption.
Teleport: Vue 3 introduced Teleport, which allows components to be rendered to different locations in the DOM tree. This is useful for creating scenarios such as modals, popups, and notification components.
Refactoring of the global API: Vue 3 refactors and improves the global API, exposing the API more consistently and controllably in the global context, providing a better development experience and maintainability.
Fragment: Vue 3 introduced Fragment, allowing components to return multiple root elements without the need for additional wrapping elements.
Improved responsive system: In addition to the Composition API, Vue 3 has made other improvements to the responsive system, providing better performance and more comprehensive feature support.

Vue 3 features numerous improvements in performance, bundle size, development experience, and functionality, allowing developers to build modern web applications more efficiently and reliably. At the same time, Vue 3 maintains backward compatibility, making migration to the new version relatively smooth.

3 Practical application cases and effect verification of Vue 3

3.1 Example Analysis: Use Vue 3 to develop a simple real-time chat application

When using Vue 3 to develop a simple real-time chat application, here is a simple example showing how to use Vue 3 to develop a real-time chat application:

Create a Vue 3 application:

npm install -g @vue/cli
vue create chat-app

Install Vue Router and Socket.io-client:

cd chat-app
npm install vue-router socket.io-client

Create a Chat component to display chat messages:

<template>
  <div>
    <div v-for="message in messages" :key="message.id">
      <strong>{
     
     {message.user}}:</strong> {
     
     {message.text}}
    </div>
    <form @submit="sendMessage">
      <input v-model="text" type="text" placeholder="Type your message" />
      <button type="submit">Send</button>
    </form>
  </div>
</template>

<script>
import {
        
         ref } from 'vue';
import io from 'socket.io-client';

export default {
        
        
  name: 'Chat',
  setup() {
        
        
    const messages = ref([]);
    const text = ref('');
    const socket = io('http://localhost:3000');

    socket.on('message', (message) => {
        
        
      messages.value.push(message);
    });

    const sendMessage = () => {
        
        
      if (text.value) {
        
        
        socket.emit('message', {
        
         user: 'Me', text: text.value });
        text.value = '';
      }
    };

    return {
        
        
      messages,
      text,
      sendMessage,
    };
  },
};
</script>

Create a ChatApp component that creates users and chat sessions:

<template>
  <div>
    <h1>Chat App</h1>
    <div v-if="!username">
      <input v-model="tempUsername" type="text" placeholder="Enter your username" />
      <button @click="createUser">Join Chat</button>
    </>
    <div v-else>
      <p>Logged in as {
     
     {username}}</p>
      <Chat />
    </div>
  </div>
</template>

<script>
import {
        
         ref } from 'vue';
import {
        
         useRouter } from 'vue-router';
import io from 'socket.io-client';

import Chat from './Chat.vue';

export default {
        
        
  name: 'ChatApp',
  components: {
        
        
    Chat,
  },
  setup() {
        
        
    const tempUsername = ref('');
    const username = ref('');
    const router = useRouter();
    const socket = io('http://localhost:3000');

    const createUser = () => {
        
        
      if (tempUsername.value) {
        
        
        username.value = tempUsername.value;
        socket.emit('user', username.value);
      }
    };

    socket.on('user-created', () => {
        
        
      router.push('/chat');
    });

    return {
        
        
      tempUsername,
      username,
      createUser,
    };
  },
};
</script>

Create a router.js file to set routing:

import {
      
       createRouter, createWebHistory } from 'vue-router';

import ChatApp from './components/ChatApp.vue';
import Chat from './components/Chat.vue';

const routes = [
  {
      
       path: '/', component: ChatApp },
  {
      
       path: '/chat', component: Chat },
];

const router = createRouter({
      
      
  history: createWebHistory(),
  routes,
});

export default router;

Modify the main.js file, load routes and create a Vue application:

import {
      
       createApp } from 'vue';
import App from './App.vue';
import router from './router';

createApp(App).use(router).mount('#app');

Create a server.js file to start the Socket.io server:

const http = require('http');
const socketIo = require('socket.io');

const server = http.createServer();
const io = socketIo(server);

const activeUsers = [];

io.on('connection', (socket) => {
      
      
  console.log('A user connected');

  socket.on('user', (username) => {
      
      
    console activeUsers.push(username);
    io.emit('user-created');
  });

  socket.on('message', (message) => {
      
      
    console.log('Message:', message);
    io.emit('message', message);
  });

  socket.on('disconnect', () => {
      
      
    console.log('A user disconnected');
  });
});

server.listen(3000, () => {
      
      
  console.log('Server started on port 3000');
});

Start the server:
```
node server.js
```
Start the Vue application:
```
npm run serve
```

This simple live chat app will allow users to enter a username and join a chat session. Users can send chat messages, which will appear instantly on all connected clients.

3.2 Case Study: Applying the performance optimization function of Vue 3 in large-scale enterprise-level projects

When applying Vue 3's performance optimization features in large enterprise-level projects, the following is a simple case analysis, including some common performance optimization features and code examples:

Component lazy loading (Lazy Loading):
code example:

const HomePage = () => import('./pages/HomePage.vue');
const AboutPage = () => import('./pages/AboutPage.vue');

const routes = [
  {
    
     path: '/', component: HomePage },
  {
    
     path: '/about', component: AboutPage }
];

const router = createRouter({
    
    
  history: createWebHistory(),
  routes
});

Here, components are loaded on demand through dynamic import, and the corresponding components will only be loaded when the corresponding route is accessed.

Reference on demand (Tree-shaking):
Code example:

import {
    
     createStore } from 'vuex';

const store = createStore({
    
    
  // ...store configuration
});

export default store;

When using Vuex in Vue 3, only introduce the parts of the library you need, not the entire library. This can reduce the size of the packaged file. Configuring Tree-shaking in build tools such as Webpack can automatically trim unused code.

Caching mechanism:
code example:

import {
    
     ref } from 'vue';

// 缓存计算结果
const cachedResult = ref(null);

function expensiveCalculation() {
    
    
  if (cachedResult.value) {
    
    
    return cachedResult.value;
  }
  
  // 执行较为耗时的计算
  const result = /* ... */;
  
  cachedResult.value = result;
  return result;
}

In this example, time-consuming calculation results are cached by using Vue 3's responsive data ref. The cached result can be returned directly the next time it is called to avoid repeated calculations.

Using Virtual Scrolling:
Code Example:

<template>
  <virtual-scroller :items="data" :item-height="itemHeight" />
</template>

<script>
import {
      
       ref } from 'vue';
import VirtualScroller from 'vue-virtual-scroller';

export default {
      
      
  components: {
      
      
    VirtualScroller
  },
  setup() {
      
      
    const data = ref(/* ... */);
    const itemHeight = ref(50); // 每项的高度

    return {
      
      
      data,
      itemHeight
    };
  }
};
</script>

In this example, Vue 3's virtual scroll component (such as vue-virtual-scroller) is used to render only the list items in the visible area to improve rendering performance, especially when processing large amounts of data.

Use SSR (server-side rendering):
You can use the SSR function of Vue 3 to complete the initial rendering of the page on the server side to provide faster first-time loading speed and better SEO. Create an SSR application using Vue's createSSRAppmethods, ensuring that the same code and state are shared between server and client.
Use Memoization to cache calculation results:
Using the Composition API of Vue 3, you can use Memoization technology to cache more complex or time-consuming calculation results to reduce calculation overhead. You can use computedfunctions or Vue 3 refto define a computed property and use memoizea library to perform caching operations, as shown below:

import {
    
     ref } from 'vue';
import memoize from 'lodash.memoize';

const expensiveCalculation = memoize((param) => {
    
    
  // 执行较为复杂或耗时的计算
  // 使用 param 进行计算

  return result;
});

export default {
    
    
  setup() {
    
    
    const param = ref(/* 参数 */);
    const result = computed(() => expensiveCalculation(param.value));

    return {
    
    
      param,
      result
    };
  }
};

Use CDN acceleration:
Publish Vue 3 and its related resources (such as Vue Router, Vuex) to CDN to make full use of CDN's caching and distribution capabilities to accelerate resource loading. Directly reference the resource link on the CDN in the HTML file, as follows:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>My Vue 3 App</title>
  <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/vue.runtime.min.js"></script>
  <!-- 引入其他 CDN 资源 -->
</head>
<body>
  <div id="app">
    <!-- 应用代码 -->
  </div>
  <script src="main.js"></script>
</body>
</html>

Please note that the above examples only demonstrate some common performance optimization functions and code examples. Actual applications require in-depth analysis and optimization based on specific needs and project conditions. At the same time, using performance monitoring tools for performance testing and evaluation is also an important step to ensure the effectiveness and stability of the optimization strategy.