JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://unpkg.com/vue/dist/vue.js"></script>

<div id="app">
  <ul>
    <li v-for="n in numbers">{{ n }}</li>
  </ul>
  
  <button v-on:click="changeNumber()">Change Number</button>
</div>

JavaScript

new Vue({
	el: '#app',
  data: {
		numbers: [1, 2, 3, 4, 5]
  },
  methods: {
    changeNumber: function() {
      Vue.set(this.numbers, this.numbers.length, 10);
      alert(this.numbers.length);
    }
  }
});