How to use global data for cross-component communication in Vue

Vue is a very popular front-end framework that provides us with a way to communicate between components more easily, making our code more modular and easier to maintain. This article mainly describes how to use Vue's global data for cross-component communication. I hope it will be helpful to beginners.

1. Vue global data

Vue global data refers to data that can be accessed in Vue applications. In Vue, we can define global data through Vue.prototype so that it can be accessed in all components. In actual development, we usually define global data before Vue is instantiated.

For example, we can define global data in main.js:

import Vue from 'vue'

Vue.prototype.$globalData = {
  username: ''
}

Here we define a global variable named $globalData and set it to an empty string. In this example, you can access this variable at any time from any component via this.$globalData.username.

2. How to use global data for cross-component communication

In actual development, there are often situations where communication needs to be carried out between parent components and child components, especially some shared states or data. At this point, we can use Vue's global data to achieve cross-component communication.

The steps are as follows:

1. We first define a global variable to store data. For example, we define a $store global variable.

import Vue from 'vue'
Vue.prototype.$store = {
  username: '',
  age: 0
}

2. Data transfer through $emit and $on between components. For example, we modify the value of the $store variable in the parent component, and then pass this change to the child component through the $emit event.

// Parent.vue

export default {
  data () {
    return {}
  },
  methods: {
    changeUsername () {
      this.$store.username = 'Jack'
      this.$emit('usernameChanged', 'Jack')
    }
  }
}

In this example, we pass the modified value to the child component by modifying $store.username and triggering a $emit event.

3. Listen to events and update the view. For example, we listen to events in child components and update the view based on the data in the event.

// Child.vue

export default {
  data () {
    return {
      username: ''
    }
  },
  created () {
    this.$parent.$on('usernameChanged', (newUsername) => {
      this.username = newUsername
    })
  }
}

In this example, we access the parent component through $parent and listen to the 'usernameChanged' event triggered by the parent component. In the event callback function, we update the username data of the child component and trigger a view update.

This is the basic process of using Vue global data for inter-component communication. Of course, in actual development, we may encounter more complex communication scenarios, but in general, this method is very practical.

Summary

This article mainly introduces how to use global data for inter-component communication in Vue. By defining global data before Vue is instantiated and using $emit and $on events for data transfer, we can easily implement communication between components. This method not only improves code reusability, but also provides us with more flexibility during the development process.

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