[Vuejs]-Vue Component, toggle data

by

3👍

✅

Updating after a correcting comment from thanksd. I stumbled onto the right answer without really understanding it.

The problem is that within the slot, display refers to an item in the scope-slot object. Updating it there does not update the actual source variable. If you pass in and call a function, the proper variable is updated.

Vue.component('dropdown', {
  props: ['expanded'],
  data: function() {
    return {
      display: Boolean(this.expanded)
    }
  },
  methods: {
    toggle() {
        this.display = !this.display;
    }
  },
  template: '<div><transition name="expand"><slot :display="display" :toggle="toggle"></slot></transition></div>'
});

new Vue({
  el: '#app'
});
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<div id="app">
  <dropdown>
    <div slot-scope="{display, toggle}">
      <a href="javascript:void(0)" @click="toggle">Toggle {{ display }}</a>
      <div v-if="display">
        Dropdown content
      </div>
    </div>
  </dropdown>
</div>
👤Roy J

1👍

One solution would be to implement a v-model for the dropdown component which would allow you to two-way bind the display property to a property in the parent. That way you wouldn’t need to pass anything via the slot-scope.

Here’s an example of that:

Vue.component('dropdown', {
  props: [ 'value' ],
  data() {
    return {
      display: !!(this.value)
    }
  },
  watch: {
    value(value) {
      this.$emit('input', value);
    }
  },
  template: '<div><transition name="expand"><slot></slot></transition></div>'
});

new Vue({
  el: '#app',
  data() {
    return { dropdownToggle: false }
  }
});
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<div id="app">
    <dropdown v-model="dropdownToggle">
      <div>
        <a href="javascript:void(0)" @click="dropdownToggle = !dropdownToggle">
          Toggle {{ dropdownToggle }}
        </a>
        <div v-if="dropdownToggle">
          Dropdown content
        </div>
      </div>
  </dropdown>
</div>
👤thanksd

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