vue has been using it for some time and doesn"t quite understand his response. The vue response has one limitation, that is,
Vue does not allow new root-level responsive attributes (root-level reactive property)) to be dynamically added to instances that have already been created. However, it can use the Vue.set (object, key, value) method to add response properties to nested objects:
then I found that I still didn"t understand when I was working on the project.
- the first case
3.
how do you explain this?