fix: state objects don't work with submodules

🐛 The bug I get the following issue during invocation of useAccessor function.

const storePattern = {
  state,
  mutations,
  modules: {
    foo,
  },
}

const store = new Vuex.Store(storePattern)

export const accessor = useAccessor(store, storePattern)

Uncaught TypeError: Cannot set property foo of #<Object> which has only a getter

🛠️ To reproduce Try to invoke useAccessor with any module, which state declared as plain object.

🌈 Expected behaviour I expect the correct module registration.

ℹ️ Additional context Add any other context about the problem here.

[danielroe]

If you have submodules defined, Vuex actually mutates the state object passed in - so that when the accessor is created, it gets a state object that is different from the one passed to Vuex.

For the moment, that means if you want to use typed-vuex you’ll need to use a state function, which doesn’t suffer from this kind of mutation by Vuex. I’ll consider whether there is a simple way to enable state object usage.

[andrewvasilchuk]

@danielroe, Thanks for the quick and comprehensive answer.