Is a computed property reactive with get() and set()?

Question

Vue.js

The Vue component has a computed property that needed to add a setter as well . But for some reason the color of the button depending on this property does not change after changing it. Reactivity is broken.
Inside the methods, we are working with a property from an external module.
Is that how it's supposed to be or did I screw up somewhere?
Example:

Answer 1

your state object is not reactive. in order for it to be such, it must either be initialized in data:

const comp = Vue.component('comp', {
  ...
  data() {
  	return state
  },
  ...
})

or do this:

const state = Vue.observable({ z: false });
const comp = Vue.component('comp', {
...