JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.21/lodash.min.js"></script>
<div id="app">
  <button @click="addData">Add</button>
</div>

JavaScript

new Vue({
	el: '#app',
    data() {
      return {
        myData: {
          time: {

          }
        }
      }
  },
  computed: {
  	computedMyData() {
    	return JSON.stringify(this.myData);
    }
  },
  watch: {
    computedMyData: {
      handler(newValJSON, oldValJSON) {
      	let newVal = JSON.parse(newValJSON),
        		oldVal = JSON.parse(oldValJSON);
            
        console.log("NEW", newVal);
        console.log("OLD", oldVal);
      },
      deep: true
    }
  },
  methods: {
    addData() {
      this.$set(this.myData.time, 'other','testing')
    }
  }
});