npm install --save @riophae/vue-treeselect

<!-- Vue SFC -->
<template>
 <div id="app">
 <treeselect v-model="value" :multiple="true" :options="options" />
 </div>
</template>

<script>
 // import the component
 import Treeselect from '@riophae/vue-treeselect'
 // import the styles
 import '@riophae/vue-treeselect/dist/vue-treeselect.css'

 export default {
 // register the component
 components: { Treeselect },
 data() {
  return {
  // define the default value
  value: null,
  // define options
  options: [ {
   id: 'a',
   label: 'a',
   children: [ {
   id: 'aa',
   label: 'aa',
   }, {
   id: 'ab',
   label: 'ab',
   } ],
  }, {
   id: 'b',
   label: 'b',
  }, {
   id: 'c',
   label: 'c',
  } ],
  }

 },
 }
</script>