CODEWITHSUNDEEP
vue.jsdynamicvuejs2vue-component
waspinator
waspinator

Reputation: 6816

listen to events from dynamic vue components

How would you listen to an event emitted by a dynamically created component instance?

In the example, the top component is added in the DOM, while the second is dynamically created in javascript. 

Vue.component("button-counter", {
  data: function() {
    return {
      count: this.initial_count
    }
  },
  props: ['initial_count'],
  methods: {
    add: function() {
      this.count++
        this.$emit('myevent', this.count)
    }
  },
  template: '<button v-on:click="add">You clicked me {{ count }} times.</button>'
})

let app = new Vue({
  el: "#app",
  data() {
    return {
      initial_count: 10,
    }
  },
  mounted: function() {
    let initial_count = this.initial_count

    let ButtonCounterComponentClass = Vue.extend({
      data: function() {
        return {}
      },
      render(h) {
        return h("button-counter", {
          props: {
            initial_count: initial_count
          }
        })
      }
    })
    let button_counter_instance = new ButtonCounterComponentClass()
    button_counter_instance.$mount()
    button_counter_instance.$on('myevent', function(count) {
      console.log('listened!')
      this.say(count)
    })
    this.$refs.container.appendChild(button_counter_instance.$el)
  },
  methods: {
    say: function(message) {
      alert(message)
    }
  }
})
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/vue.js"></script>

<div id="app">
    <button-counter initial_count=20 v-on:myevent="say"></button-counter>
    <div ref='container'></div>
</div>

Upvotes: 2

Views: 1060

Answers (1)

skirtle
skirtle

Reputation: 29092

If I've understood what you want then you just need to listen for the event on the inner component and pass it on.

I've used arrow functions in a couple of places to avoid problems with this bindings. Otherwise I've tried to leave your code unchanged as much as possible. Changes marked with ****.

Vue.component("button-counter", {
  data: function() {
    return {
      count: this.initial_count
    }
  },
  props: ['initial_count'],
  methods: {
    add: function() {
      this.count++
        this.$emit('myevent', this.count)
    }
  },
  template: '<button v-on:click="add">You clicked me {{ count }} times.</button>'
})

let app = new Vue({
  el: "#app",
  data() {
    return {
      initial_count: 10,
    }
  },
  mounted: function() {
    let initial_count = this.initial_count

    let ButtonCounterComponentClass = Vue.extend({
      data: function() {
        return {}
      },
      render(h) {
        return h("button-counter", {
          props: {
            initial_count: initial_count
          },
          // **** Added this ****
          on: {
            myevent: count => {
              this.$emit('myevent', count);
            }
          }
          // ****
        })
      }
    })
    let button_counter_instance = new ButtonCounterComponentClass()
    button_counter_instance.$mount()
    // **** Changed the next line ****
    button_counter_instance.$on('myevent', count => {
      console.log('listened!')
      this.say(count)
    })
    this.$refs.container.appendChild(button_counter_instance.$el)
  },
  methods: {
    say: function(message) {
      alert(message)
    }
  }
})
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/vue.js"></script>

<div id="app">
    <button-counter initial_count=20 v-on:myevent="say"></button-counter>
    <div ref='container'></div>
</div>

It's important to understand that button_counter_instance is not an instance of your button-counter component. You've wrapped it in another component, albeit a component that doesn't add any extra DOM nodes. So listening on the wrapper component is not the same as listening on button-counter.

Docs for what you can pass to h: https://v2.vuejs.org/v2/guide/render-function.html#The-Data-Object-In-Depth

Upvotes: 4

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