Optimization skills and practical experience of list rendering in Vue

Optimization skills and practical experience of list rendering in Vue

Preface
In the process of developing web applications using Vue, list rendering is a common requirement. However, when there is a large amount of data in the list, frequent DOM operations may cause page performance to degrade. In order to solve this problem, this article will introduce some list rendering optimization techniques in Vue, and provide practical experience and code examples.

1. Avoid using index as the key value

When using v-for loop to render a list in Vue, you need to provide a key value to uniquely identify each item. In some cases, developers may prefer to use a circular index as the key value. However, this approach is not recommended.

There are some problems with using index as the key value. When the order in the list changes, Vue will re-render the DOM through the diff algorithm. If you use index as the key value, it may cause some unnecessary DOM operations, thereby reducing performance. Therefore, we should use the unique identifier of each item as the key value.

For example:

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

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2. Use v-show instead of v-if

In Vue, both v-if and v-show can control the display and hiding of DOM elements. However, v-if has some additional overhead, as it completely recreates or destroys the DOM element. And v-show only hides or shows DOM elements by modifying CSS properties. Therefore, when we need to frequently switch the display and hiding of list items, we should use v-show instead of v-if.

For example:

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<li v-for="item in items" :key="item.id" v-show="item.visible">{{ item.name }}</li>

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3. Use local component cache

When each item in a list corresponds to a more complex component, we can use the local component cache provided by Vue to improve performance. By placing the component definition within the 7c9485ff8c3cba5ae9343ed63c2dc3f7 tag, Vue will cache already rendered components when switching between components, thereby avoiding repeated DOM operations.

For example:

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<keep-alive>
  <item :key="item.id" v-for="item in items"></item>
</keep-alive>

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4. Use virtual lists

When the amount of data in the list is very large, we can use virtual lists to optimize rendering performance. A virtual list will only render the currently visible list items, rather than the entire list. Virtual lists can be implemented by dynamically calculating the position and size of each list item.

The following is an example of using vue-virtual-scroll-list, a Vue-based virtual list plug-in:

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<virtual-list :size="items.length" :remain="10">
  <template v-slot="{ range }">
    <li v-for="index in range" :key="items[index].id">{{ items[index].name }}</li>
  </template>
</virtual-list>

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5. Use paging loading

When the amount of list data is too large, you can use paging loading to reduce one-time loading The impact of large amounts of data on page performance. By dividing the list into multiple pages, only loading the data of the current page each time, and providing the function of paging switching, the rendering pressure of the page can be effectively reduced.

The following is an example of using vue-infinite-scroll, a Vue-based paging loading plug-in:

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

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<button @click="loadMore">Load More</button>

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import InfiniteScroll from 'vue-infinite-scroll'

export default {
data() {

return {
  items: [],
  page: 1
}

},
methods: {

loadMore() {
  // AJAX请求获取下一页数据
  // this.items = [...this.items, ...newData]
  this.page++
}

},
mounted() {

// 初始化分页加载插件
// this.$refs.infiniteScroll.addEventListener('scrolled', this.loadMore)

},
beforeDestroy() {

// 销毁分页加载插件
// this.$refs.infiniteScroll.removeEventListener('scrolled', this.loadMore)

}
}
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Conclusion
Through the above optimization skills and practical experience, we can handle list rendering more efficiently in Vue , optimize page performance. Reasonable selection of key values, use of v-show, local component caching, virtual lists, and paging loading can improve page rendering speed and user experience. I hope this article will be helpful to you in the process of using list rendering in Vue.

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