How to do when you select a value in the first select, the second select appears according to the fields belonging to the selected first select?

Question

Vue.js

How to make a comparison with the selected select?
My example
Example:

Answer 1

You should have several objects
1 object describes the options that are selected and you save the selected option in the data property of the selected_contact type
2 object is already dependent objects from the selected_contact option selected by keys, and you just make a connection
For example

contacts: [
   {title: 'one', value: 'one'},
   {title: 'two', value: 'two'},
],
dependence: {
  one: [
     {title: 'dep_one1', value: 'one1'},
     {title: 'dep_one2', value: 'two1'},
     ....
  ],
  two: [
     {title: 'dep_two1', value: 'two1'},
     {title: 'dep_two2', value: 'two2'},
     ....
  ]
}