The difference between Vue3 and Vue2: better code reusability

The difference between Vue3 and Vue2: Better code reusability

Vue.js is a popular front-end framework that is widely used to build single-page applications. With the continuous development and updating of Vue.js, Vue2 has become the first choice of many developers. However, the recently released Vue3 will further improve code reusability and provide developers with a more convenient and efficient development experience. This article will compare Vue3 and Vue2 from different perspectives, focusing on the advantages of Vue3 in code reusability.

1. Composition API
   Vue3 introduces the Composition API, which is a new combined API that provides a more flexible and efficient way to reuse components. Compared with Vue2's Options API, the Composition API encapsulates logical functions in the form of functions, which is more intuitive and easier to understand. Developers can define their own logical functions as needed and reference them in components as needed. This approach allows developers to better organize and reuse code, improving the maintainability and reusability of the code.

The following is an example comparing the way components are reused in Vue2 and Vue3:

The way in Vue2:

// 定义一个混入
var myMixin = {
  created: function () {
    this.hello()
  },
  methods: {
    hello: function () {
      console.log('Hello from mixin!')
    }
  }
}

// 使用混入
Vue.component('my-component', {
  mixins: [myMixin],
  methods: {
    greeting: function () {
      console.log('Hello from component!')
    }
  }
})

The way in Vue3:

// 定义一个逻辑函数
function useGreeting() {
  function hello() {
    console.log('Hello from composition function!')
  }

  return {
    hello
  }
}

// 使用逻辑函数
Vue.component('my-component', {
  setup() {
    const { hello } = useGreeting()

    function greeting() {
      console.log('Hello from component!')
    }

    return {
      greeting,
      hello
    }
  }
})

As you can see, using the Composition API is clearer and more concise in terms of code structure and writing style. Developers can split different logical functions and reference them as needed in the setup function of their own components to achieve better code reuse.

2. Fragment
   Vue3 provides the Fragment component, which makes the component structure more flexible. In Vue2, a component must have a root element to wrap child elements, but in some scenarios, this restriction may not apply. The Fragment component introduced in Vue3 allows developers to return multiple root elements in one component, which can better cope with complex layout requirements.

The following is an example of using Fragment:

The way in Vue2:

<template>
  <div>
    <h1 id="Title">Title</h1>
    <p>Content</p>
  </div>
</template>

The way in Vue3:

<template>
  <Fragment>
    <h1 id="Title">Title</h1>
    <p>Content</p>
  </Fragment>
</template>

3. Teleport
   Teleport is a new feature in Vue3, which can render the content of the component to a specified location in the DOM tree. This is very useful in some specific scenarios, such as in pop-up components, where the pop-up content usually needs to be inserted into the body element. Teleport in Vue3 allows developers to implement such components more conveniently, improving code reusability and maintainability.

The following is an example of using Teleport:

<template>
  <div>
    <button @click="showModal">Show Modal</button>
    <teleport to="body">
      <modal v-if="show">
        <h2 id="Modal-Title">Modal Title</h2>
        <p>Modal Content</p>
      </modal>
    </teleport>
  </div>
</template>

As you can see, using Teleport you can render the content of the modal component under the body element instead of nesting it directly in the component. , which greatly improves the reusability of components.

Summary:
Vue3 further improves the reusability of code by introducing features such as Composition API, Fragment and Teleport. Developers can better organize and reuse code, improving development efficiency and code quality. With the continuous development and use of Vue3, I believe it will become the choice of more and more developers and play a more important role in front-end development.

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