How to change class from false to true in Vue?

Question

JavaScript

Hello. Tell me, please, how to change the class in View from false to true after 4 seconds?

var body = new Vue({
  el:'#main',
  data:{
    active_color: false
  },
  methods:{
    ChangeColor: function(){
          setTimeout(()=>{
          	this.active_color = true;
          },40000)
    }
  }
});

Answer 1

Actually, it works fine. https://jsfiddle.net/L0ay4jwh/