JSFiddle - React, Tailwind, and code Playground

HTML

<div id="app">
  <pre>{{ obj }}</pre>
  <pre>{{ arr }}</pre>
</div>

JavaScript

new Vue({
  el: '#app',
  data: () => ({
    obj: {
      foo: 42
    },
    arr: ['lorem', 'dolor']
  }),
  mounted () {
    this.obj.bar = 48
    this.arr[1] = 'ipsum'
  }
})