The difference between Vue3 and Vue2: faster official update iteration

The difference between Vue3 and Vue2: faster official update iteration

Introduction:
Vue.js is a popular JavaScript framework that is widely used to build interactive web applications. The latest version of Vue.js is Vue3. Compared with the previous version Vue2, Vue3 has significant improvements and upgrades in performance, development experience and functions. This article will focus on the differences between Vue3 and Vue2, and illustrate its specific improvements through code examples.

1. Performance improvement
Vue3 has made many optimizations in terms of performance, which has improved the performance of the application. The most noteworthy thing is that Vue3 uses Proxy as the implementation method of data hijacking. Compared with Vue2's Object.defineProperty, Proxy is more efficient in performance. The following is a code example comparing Vue3 and Vue2:

Vue3 example:

const reactiveObj = {
  count: 0
}

const proxyObj = new Proxy(reactiveObj, {
  set(target, key, value) {
    target[key] = value
    console.log('数据更新了', target)
    return true
  }
})

proxyObj.count = 1

Vue2 example:

const reactiveObj = {
  count: 0
}

Object.defineProperty(reactiveObj, 'count', {
  set(newValue) {
    console.log('数据更新了', newValue)
  }
})

reactiveObj.count = 1

As can be seen from the above code example, Vue3 uses Proxy Perform data hijacking more concisely and efficiently. Vue2 needs to use Object.defineProperty, which requires more code and is not intuitive enough.

2. Development experience upgrade
Vue3 has made a series of improvements in the development experience, allowing developers to develop and maintain Vue applications more efficiently. The most obvious improvement is the introduction of the Composition API. Its function-based API provides a more flexible and composable component development method. The following is an example of using the Vue3 Composition API:

import { reactive, ref, onMounted } from 'vue'

export default {
  setup() {
    const state = reactive({
      count: ref(0)
    })

    onMounted(() => {
      console.log('组件已经挂载')
    })

    const increment = () => {
      state.count.value++
    }

    return {
      state,
      increment
    }
  }
}

As you can see from the above code, Vue3 introduces the Composition API through the setup function. Developers can use reactive, ref and other functions to create responsive data. At the same time, you can also use life cycle hooks such as onMounted in the setup function. In contrast, Vue2 uses the Options API, which requires defining and managing data and logic in different hook functions, which is not flexible and composable enough.

3. Function enhancement
In addition to improvements in performance and development experience, Vue3 has also added some new features to make it more powerful in functionality. For example, Vue3 introduced the Teleport component for rendering components at different locations in the DOM tree, which is not supported in Vue2. The following is an example of using the Teleport component:

<template>
  <div>
    <h1 id="Vue-Teleport示例">Vue3 Teleport示例</h1>
    <teleport to="body">
      <div class="modal">
        <h2 id="这是一个模态框">这是一个模态框</h2>
      </div>
    </teleport>
  </div>
</template>

<script>
import { defineComponent } from 'vue'

export default defineComponent({
  name: 'App',
  // ...
})
</script>

In the above example, the Teleport component can render the modal box under the body tag, so that the component can be rendered at different locations in the DOM tree to achieve more flexibility. layout.

Conclusion:
In summary, Vue3 has significantly improved performance, development experience and functionality compared to Vue2. Vue3 uses a more efficient Proxy as the implementation method of data hijacking to improve performance; it introduces the Composition API to make development more flexible and composable; it adds new functions such as Teleport, further increasing the functionality of the framework. Therefore, for new Vue projects or upgrades of old projects, we should give priority to Vue3 to get faster official update iterations and a better development experience.

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