angular.js - How to use angular to implement three-level linkage of an array

Question

The array looks like this

I want to use angular to realize the three-level linkage of provinces and municipalities. The current code looks like this, but the result cannot be realized. Can't get city

Answer 1

It’s useless for you to write like this

Answer 2

I asked a very stupid question = =Using ng-change to change the state according to the previous level can achieve three-level linkage