reducer

const newAuthStore = newStoreDef({
  reducer({ prevState, state, action, set, async, diff, optimistic, store }) {
    if (action.type === "set-name") {
      optimistic({ name: action.name })
      set({ name: action.name })
    }
 
    if (diff(["name"])) {
      async
        .promise(async ({ signal }) => {
          const users = await listUsers(state.name, signal)
          return users
        })
        .onSuccess((users, actor) => {
          actor.set({ $users: users })
        })
    }
 
    return state
  },
})