Nested vue-draggable elements

Question

I am trying to have nested vue-draggable elements to visually represent a song structure (with potential repetitions).

This is what I came up with as a prototype:

var vm = new Vue({
  el: "#main",
  data: {
    "structure": ["Prelude", "Verse", ["Chorus", "Verse"], "Last Chorus"]
  },
});

#main {
  text-align: center;
  width: 300px;
  background-color: #EEE;
  padding:10px;
}

.element {
  text-align: center;
  padding: 10px;
  margin: 5px auto;
  border-radius: 10px;
  color: #FFF;
  font-family: sans-serif;
  font-weight: bold;
}

.tag {
  width: 150px;
  background-color: #007BFF;
}

.group {
  width: 175px;
  border: 3px solid #CED4DA;
  background-color: #FFF;
}

<script src="//cdnjs.cloudflare.com/ajax/libs/vue/2.5.2/vue.min.js"></script>
<script src="//cdn.jsdelivr.net/npm/[email protected]/Sortable.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/Vue.Draggable/2.15.0/vuedraggable.min.js"></script>

<div id="main">
  <draggable v-for="tag in structure" :options="{group:'tags'}">
    <div v-if="!Array.isArray(tag)" class="tag element">
      {{tag}}
    </div>
    <draggable v-else :options="{group:'tags'}" class="group element">
      <div v-for="tag2 in tag" class="tag element">
        {{tag2}}
      </div>
    </draggable>
  </draggable>
  {{structure}}
</div>

Even being new to Vue.js this seems so not "the way" to go. My concrete problems with this solution are:

• When the grouping element is at the top, I can't drag anything else above it (same applies to the very bottom)
• The dragged structure does not get represented in the data.structure property
• How would I go about nesting even more? Group in group in group...

Answer 1

You should:

1. Change the data structure into a recursive one:

 data: {
    "structure": [
       { name: "Prelude"}, 
       { name: "Verse"}, 
       { name: "Middle", children: [{ name: "Chorus"}, { name: "Verse"}]}, 
       { name: "Last Chorus"}
    ]
  },

2. Use recursive components using draggable, something like:

<template>
  <draggable class="dragArea" tag="ul" :list="data" :group="{ name: 'g1' }">
    <li v-for="el in children" :key="el.name">
      <p>{{ el.name }}</p>
      <nested-draggable v-if="el.children" :tasks="el.children" />
    </li>
  </draggable>
</template>

See this working example:

https://sortablejs.github.io/Vue.Draggable/#/nested-example