Virtual DOM optimization techniques in Vue 3 to improve page performance

Virtual DOM optimization techniques in Vue 3 to improve page performance

Introduction:
With the continuous development of front-end technology, virtual DOM has become a modern front-end framework an integral part of. As one of the most popular front-end frameworks on the market, Vue also uses virtual DOM to improve page rendering performance. In Vue 3, the development team further optimized the virtual DOM and provided some tips and methods to further improve the performance of the page. This article will introduce some virtual DOM optimization techniques in Vue 3, with code examples.

1. Use Fragment to reduce useless tags

In Vue 3, you can use Fragment to wrap a group of elements without generating redundant tags in the final rendered DOM tree. This can reduce the time of virtual DOM generation and comparison and improve the rendering performance of the page.

<template>
  <div>
    <h1>这是标题</h1>
    <ul>
      <li v-for="item in list" :key="item.id">{{ item.name }}</li>
    </ul>
  </div>
</template>

In the above code, the div tag is just to wrap the content and has no actual meaning. You can use Fragment to replace it:

<template>
  <fragment>
    <h1>这是标题</h1>
    <ul>
      <li v-for="item in list" :key="item.id">{{ item.name }}</li>
    </ul>
  </fragment>
</template>

2. Reasonable use of dynamic components

In Vue 3, you can use the and components to optimize the rendering of dynamic components. Use to render the content of the component into the specified DOM element without creating additional levels in the DOM tree; use to display the loading status when loading the component asynchronously, improving user experience. .

<template>
  <div>
    <h1>{{ title }}</h1>
    <teleport to="body">
      <Modal v-if="showModal" @close="showModal = false">
        内容
      </Modal>
    </teleport>
    <button @click="showModal = true">打开模态框</button>
  </div>
</template>

3. Avoid unnecessary responsive data

In Vue 3, you can use data marked as non-responsive to avoid unnecessary data changes, thereby improving the rendering performance of the page. . Using ref in the setup function can wrap ordinary data into responsive data.

<template>
  <div>
    <h1>{{ count }}</h1>
    <button @click="incrementCount">增加</button>
  </div>
</template>

<script>
import { ref } from 'vue';

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

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

    return {
      count,
      incrementCount,
    };
  },
};
</script>

4. Reasonable use of v-if and v-show instructions

In Vue 3, both v-if and v-show instructions can be used to control the display and hiding of components or elements. , but there are different application scenarios in different situations.

v-if renders the conditional block lazily. It will only be rendered when the condition is true, otherwise there will be no rendering overhead. Suitable for scenarios that require frequent switching.

v-show controls the display and hiding by modifying the CSS style of the element. The element will always remain in the real DOM, and it only needs to switch the "display" attribute in CSS. Suitable for scenes that are initially hidden but switched infrequently.

5. Proper use of list rendering and key attributes

In Vue 3, when using the v-for directive for list rendering, you need to add a unique key attribute to each item. In this way, Vue can quickly compare the differences in the virtual DOM tree based on the key attributes, thereby reducing unnecessary re-rendering.

<template>
  <ul>
    <li v-for="item in list" :key="item.id">{{ item.name }}</li>
  </ul>
</template>

6. Use Composition API to optimize logic reuse

In Vue 3, Composition API provides a more flexible and powerful way of logic reuse, which can combine related logic together. Improve code readability and reusability.

<template>
  <div>
    <h1>{{ count }}</h1>
    <button @click="increment">增加</button>
    <button @click="decrement">减少</button>
  </div>
</template>

<script>
import { ref } from 'vue';

export default {
  setup() {
    const count = ref(0);
    
    function increment() {
      count.value++;
    }
    
    function decrement() {
      count.value--;
    }

    return {
      count,
      increment,
      decrement,
    };
  },
};
</script>

Summary:
This article introduces virtual DOM optimization techniques in Vue 3, and attaches code examples. Through the reasonable use of Fragments, dynamic components, unnecessary responsive data, v-if and v-show instructions, list rendering and key attributes, and Composition API, we can further optimize the performance of the page and improve the user experience. I hope this article can help you optimize performance in Vue development.

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