The difference between Vue3 and Vue2: better front-end engineering

The difference between Vue3 and Vue2: better front-end engineering

In recent years, Vue.js has become one of the popular frameworks for front-end development. As a fast, flexible, and easy-to-use front-end framework, Vue.js brings us a lot of convenience during the development process. In the recently released Vue.js 3, we can see that it has better front-end engineering features than the previous version Vue.js 2. This article will use code examples to compare the differences between Vue.js 3 and Vue.js 2, and analyze their impact on front-end development.

1. Composition API

In Vue.js 3, a new composition API (Composition API) is introduced to replace the previous Options API. Through this new API, we can organize and reuse code more conveniently, making the code easier to maintain and understand.

The sample code is as follows:

Options API of Vue.js 2:

export default {
  data() {
    return {
      count: 0,
    };
  },
  methods: {
    increment() {
      this.count++;
    },
    decrement() {
      this.count--;
    },
  },
};

Composition API of Vue.js 3:

import { ref } from 'vue';

export default {
  setup() {
    const count = ref(0);

    function increment() {
      count.value++;
    }

    function decrement() {
      count.value--;
    }

    return {
      count,
      increment,
      decrement,
    };
  },
};

As you can see, In the Composition API of Vue.js 3, we use the setup function to declare and define data and methods. Use the ref function to create responsive data, and use the return statement to expose the data and methods that need to be provided to the template.

2. Better TypeScript support

In Vue.js 3, the support for TypeScript is more complete. By typing reactive data, we can catch many potential errors during development. This makes us more comfortable when writing and maintaining code.

The sample code is as follows:

Options API of Vue.js 2:

export default {
  data() {
    return {
      name: '',
      age: 0,
    };
  },
  methods: {
    submit() {
      if (this.name && this.age) {
        // ...
      }
    },
  },
};

Composition API TypeScript of Vue.js 3:

import { ref } from 'vue';

interface User {
  name: string;
  age: number;
}

export default {
  setup() {
    const name = ref('');
    const age = ref(0);

    function submit() {
      if (name.value && age.value) {
        // ...
      }
    }

    return {
      name,
      age,
      submit,
    };
  },
};

By pairing# By defining the types of ##name and age, we can reduce the occurrence of type errors during the development process.

3. More efficient virtual DOM

In Vue.js 3, the processing of virtual DOM has been optimized, resulting in significant improvement in rendering performance. Vue.js 3 uses a Proxy-based reactive system to minimize responsive data tracking and dependency collection. This means that when a component is re-rendered, only the parts that really need to be updated will be re-calculated and rendered, thus greatly improving rendering performance.

4. Better Tree-shaking support

Since Vue.js 3 introduces more fine-grained module imports, the effect of Tree-shaking has been improved. In Vue.js 3, we can import the required modules on demand, making the packaged code more streamlined, reducing unnecessary code volume, and improving the loading speed of the application.

The sample code is as follows:

Vue.js 2:

import Vue from 'vue';
import App from './App.vue';

new Vue({
  render: (h) => h(App),
}).$mount('#app');

Vue.js 3:

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

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

You can see that in Vue.js 3 , we used the

createApp function to create a Vue instance instead of directly introducing the Vue class. This change allows the required modules to be imported on demand during packaging, improving the quality of the packaged code.

To sum up, Vue.js 3 has more advantages in front-end engineering than Vue.js 2. Through Composition API, better TypeScript support, more efficient virtual DOM and better Tree-shaking support, we can organize and reuse code more easily, reduce potential errors, and improve application performance and loading speed. Therefore, choosing Vue.js 3 as the front-end development framework in the project is a better choice.

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