VUE on a data object and change the array responsive objects adding attributes issues

Array:

According VUE official website:

 

 

Array Modified:

　　Modify the value of an array element:

　　　　Vue.set(this.items, indexOfItem, newValue)；

　　　　this.$set(this.items, indexOfItem, newValue);

　　　　this.items.splice(indexOfItem, 1, newValue);

　  Modifying the length of the array: vm.items.splice (newLength);

 

Object:

　　Responsive to an array of newly added attributes:

　　　　Vue.set(vm.userProfile, 'age', 27);

　　　　vm.$set(vm.userProfile, 'age', 27);

　　While adding more properties:

　　　　vm.userProfile = Object.assign({}, vm.userProfile, { age: 27, favoriteColor: 'Vue Green' })