JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://unpkg.com/[email protected]/dist/vue.js"></script>
<div id="app">
  {{item}}
</div>

JavaScript

var someExternalObject = { thing: 'some value' }

var vm = new Vue({
  el: '#app',
  computed: {
    item() {
      return someExternalObject.thing;
    }
  },
})

setTimeout(() => {
  someExternalObject.thing = 'new value';
  console.log(someExternalObject.thing);
}, 1000)