Does vue v-for need an event proxy?

In Vue development, v-for is an important instruction. It can help us quickly render lists, which greatly facilitates our development work and also improves our development efficiency. When using v-for, some developers will be concerned about one issue, that is, whether they need to use an event proxy.

The v-for instruction provided by Vue is essentially a loop. It will loop to generate some elements or components with the same HTML structure based on the data source. Although this method can quickly implement list rendering, it also brings certain performance issues.

When we use event binding in a v-for loop, such as a click event, each element or component generated by the loop will be bound to the same event handler. If we need to bind an event handler to a list of 1,000 records, this approach will cause a decrease in browser performance and make the user experience worse.

A common solution to this problem is event proxy. Event proxy is a mechanism that uses event bubbling to delegate the triggering of events to the parent element for processing. This method only needs to bind the event processing function once, which reduces a large number of event bindings and thus improves browser performance.

So, in Vue development, does v-for need an event proxy? This question should be considered on a case-by-case basis. If our list only has a few records and only needs to bind a small number of event handling functions, then we do not need to use an event proxy. However, if our list is very large, such as hundreds, thousands or even more records, and we need to bind many event processing functions, then we need to use an event proxy.

So, how to implement event proxy? Vue provides the @ symbol to bind events. If you need to use an event proxy, you only need to bind the event on the parent element, and then get the target element in the event handler function to proxy the event of the child element.

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

<script>
export default {
  data() {
    return {
      list: [
        {id: 1, name: 'a'},
        {id: 2, name: 'b'},
        {id: 3, name: 'c'},
      ]
    }
  },
  methods: {
    handleClick(e) {
      if (e.target.tagName === 'LI') {
        // 处理点击事件
      }
    }
  }
}
</script>

In the above code, we bind the click event to the parent element ul, obtain the target element in the event processing function, and then proxy the click event of the child element li.

In short, in Vue development, the use of v-for directive is very common, but when the list is very large, you should pay attention to using event proxy to reduce event binding and improve performance.

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