vuejs reactivity without template

javascript, vue.js, vuejs2

Solution

You can `watch` props and use empty `render` function if you don't need to create any DOM elements:

new Vue({
  el: '#app',
  data: {
    word: ''
  },
  components: {
    'child' : {
      props: ['myprop'],
      watch: {
       myprop: function(n, o) {
          console.log('changed to: ', n)
        }
      },
      render: function(h) {
       return h() // avoid warning message
      }
    }
  }
});

<script src="https://unpkg.com/vue/dist/vue.js"></script>

<div id="app">
  <child :myprop="word"></child>
  <button @click="word = 'one'">One</button>
  <button @click="word = 'two'">Two</button>
  <button @click="word = 'three'">Three</button>
</div>

Problem

I have a Vue component with an empty template that needs to listen to prop changes: ``` // component.vue <template> </template> <script> export default { props: ['mode'], updated: function() { console.log('updated!') } } </script> //parent.vue <template> ... <childcomponent :mode="variable"></childcomponent> </template> ... ``` Now whenever the parent's `variable` changes, I would expect `childcomponent.updated` to be called. However, this only seems to happen if the prop is used in the child's template. The only workaround I came up with so far is to set the child component's template to `<div v-show="false>{{ mode }}</div>`, but that really doesn't seem right? Is there a nicer way to solve my issue? The reason I'm using an empty template in the first place is because the component interacts with js library that does a bunch of DOM manipulations itself.

Original source