Question

What are the caveats of object changes detection?

Answer 1

Vue cannot detect changes for the object in property addition or deletion., Lets take an example of user data changes,

var vm = new Vue({
  data: {
    user: {
      name: 'John'
    }
  }
})

// `vm.name` is now reactive

vm.email = john@email.com // `vm.email` is NOT reactive

You can overcome this scenario using the Vue.set(object, key, value) method or Object.assign(),

Vue.set(vm.user, 'email', john@email.com);
(or)
vm.user = Object.assign({}, vm.user, {
  email: john@email.com
})