Cannot make vue.js element-ui's dialog work wh

Question

Here is the parent component:

<template lang="pug">
  .wrapper
    el-button(type="primary", @click="dialogAddUser = true") New User
    hr
    // Dialog: Add User
    add-edit-user(:dialog-visible.sync="dialogAddUser")
</template>

<script>
import * as data from '@/components/partials/data'
import AddUser from './partials/AddUser'

export default {
  name: 'users',
  components: { AddUser },

  data () {
    return {
      users: data.users,
      dialogAddUser: false
    }
  }
}
</script>

Here is the child component:

<template lang="pug">
  el-dialog(width="75%", title="New User", :visible.sync="dialogVisible", top="5vh")
    div 'el-dialog-body' - content goes here
</template>

<script>
  export default {
    name: 'add-user',
    props: {
      dialogVisible: Boolean
    }
  }
</script>

I am able to open the dialog but when close the dialog using top right button inside the dialog then I am getting this error:

Avoid mutating a prop directly since the value will be overwritten whenever the parent component re-renders. Instead, use a data or computed property based on the prop's value. Prop being mutated: "dialogVisible"

Later I tried to play and did something like below, but now I cannot even open the dialog:

<template lang="pug">
  el-dialog(width="75%", title="New User", :visible.sync="visibleSync", top="5vh")
    div 'el-dialog-body' - content goes here 
</template>

<script>
  export default {
    name: 'add-user',
    props: {
      dialogVisible: Boolean
    },
    watch: {
      visibleSync (val) {
        this.$emit('update:dialogVisible', val)
      }
    },
    data () {
      return {
        visibleSync: this.dialogVisible
      }
    }
  }
</script>

Answer 1

If visible.sync works, the component is emitting an update:visible event.

So, to not mutate in the child and, instead, propagate the event to the parent, instead of:

:visible.sync="dialogVisible"

Do

:visible="dialogVisible", v-on:update:visible="visibleSync = $event"

Full code:

<template lang="pug">
  el-dialog(width="75%", title="New User", :visible="dialogVisible", v-on:update:visible="visibleSync = $event", top="5vh")
    div 'el-dialog-body' - content goes here 
</template>

<script>
  export default {
    name: 'add-user',
    props: {
      dialogVisible: Boolean
    },
    watch: {
      visibleSync (val) {
        this.$emit('update:dialogVisible', val)
      }
    },
    data () {
      return {
        visibleSync: this.dialogVisible
      }
    }
  }
</script>

---

As another alternative, you could emit directly from the v-on listener and do without the visibleSync local property:

<template lang="pug">
  el-dialog(width="75%", title="New User", :visible="dialogVisible", v-on:update:visible="$emit('update:dialogVisible', $event)", top="5vh")
    div 'el-dialog-body' - content goes here 
</template>

<script>
  export default {
    name: 'add-user',
    props: {
      dialogVisible: Boolean
    }
  }
</script>