Vue component communication: using $bus for global event communication

Vue component communication: using $bus for global event communication

In Vue development, communication between components is a common problem. Vue provides a variety of ways to implement communication between components. One of the simple and flexible ways is to use $bus for global event communication.

$bus is an extended attribute of the Vue instance, which can be regarded as a central event bus. Through $bus, we can publish events anywhere and subscribe to events anywhere.

Implement global event communication

First, create a global event bus in the Vue instance:

// main.js
import Vue from 'vue'

Vue.prototype.$bus = new Vue()

Then, in the components that need to communicate, you can use this.$busAccess the global event bus. You can subscribe to events through the $on method and publish events through the $emit method.

The following is an example, assuming there are two components A and B. Component A triggers an event by clicking a button, and component B subscribes to the event and performs the corresponding operation after receiving the event.

// ComponentA.vue
<template>
  <div>
    <button @click="onClick">点击触发事件</button>
  </div>
</template>

<script>
export default {
  methods: {
    onClick() {
      this.$bus.$emit('event', 'Hello from Component A')
    }
  }
}
</script>

// ComponentB.vue
<template>
  <div>
    <p>{{ message }}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      message: ''
    }
  },
  mounted() {
    this.$bus.$on('event', (msg) => {
      this.message = msg
    })
  }
}
</script>

In the above example, after the button in component A is clicked, an event named 'event' will be published through the this.$bus.$emit method and a message will be delivered as parameters. Component B subscribes to the same event through the this.$bus.$on method and updates the message property after receiving the event.

Notes

Using $bus for global event communication has the advantages of simplicity and flexibility, but you also need to pay attention to the following points:

1. In components When destroyed, the event subscription needs to be manually canceled to prevent memory leaks.

   // ComponentB.vue
   beforeDestroy() {
     this.$bus.$off('event')
   }

2. Since all components have access to the global event bus, a namespace is required to distinguish events published by different components. This can be accomplished by prefixing the event name with the component name.

   // 组件A中发布的事件
   this.$bus.$emit('A:event', 'Hello from Component A')
   
   // 组件B中订阅的事件
   this.$bus.$on('A:event', (msg) => {
     // 处理事件
   })

3. When the application is large and has many components, a global event bus can cause the code to become cluttered and difficult to maintain. Therefore, it is recommended to use the global event bus in your project only when necessary, and in other cases, consider using state management tools such as Vuex or dedicated component communication methods.

The above is how to use $bus for global event communication. Through simple code examples, we can clearly understand how to implement communication between components in Vue. It is recommended that in actual projects, appropriate communication methods be selected according to specific needs to improve the maintainability and scalability of the code.

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