Cross-component communication is a common problem that developers face when building applications with Vue.js, especially when using the single-file components (SFC) structure. In this article, we will discuss various techniques and best practices for solving cross-component communication issues in Vue.js.

1. Event Bus One of the most common solutions to cross-component communication is to use an event bus. This is a global object that allows components to communicate with each other without having direct access to one another. The event bus can be implemented as a Vue instance, and events can be emitted from any component and listened for by any other component.

// EventBus.js
import Vue from 'vue'
export const EventBus = new Vue()

// Component A
this.$emit('event-name', data)

// Component B
EventBus.$on('event-name', function(data) {
  console.log(data)
})

2. Prop and Emits Vue.js provides a built-in way to pass props down the component hierarchy, and emit custom events from child components back up to their parents.

Parent Component:

<child-component :data="parentData" @child-event="handleEvent"></child-component>

Child Component:

<button @click="emitEvent">Click me</button>

methods: {
  emitEvent() {
    this.$emit('child-event', this.data)
  }
}

3. Using Inject and Provide Vue.js also provides a way to inject props from a parent component into a child component, which can be useful for passing down complex data structures.

Parent Component:

<child-component></child-component>

provide: {
  parentData: this.data
}

Child Component:

computed: {
  data() {
    return this.$inject.parentData
  }
}

4. Using Mixins Mixins can be used to share logic between components without having to repeat it in each component.

Parent Component:

<child-component></child-component>

mixins: [someMixin]

Child Component:

computed: {
  data() {
    return this.parentData
  }
}

By utilizing the above techniques, you can effectively solve cross-component communication issues in Vue.js and build more robust and maintainable applications.