Menentukan Tipe Slice dan Thunk Redux Toolkit

import { createSlice, createAsyncThunk } from "@reduxjs/toolkit";

interface UserState {
  users: User[];
  loading: boolean;
  error: string | null;
}

const initialState: UserState = {
  users: [],
  loading: false,
  error: null,
};

const userSlice = createSlice({
  name: "users",
  initialState,
  reducers: {
    setLoading(state, action: PayloadAction<boolean>) {
      state.loading = action.payload; // state: UserState — typed
    },
  },
});

import { PayloadAction } from "@reduxjs/toolkit";

reducers: {
  addUser(state, action: PayloadAction<User>) {
    state.users.push(action.payload); // action.payload: User
  },
}

const fetchUsers = createAsyncThunk<User[], void, { rejectValue: string }>(
  "users/fetchAll",
  async (_, { rejectWithValue }) => {
    try {
      return await api.getUsers();
    } catch (e) {
      return rejectWithValue("Failed to fetch");
    }
  }
);

const userSlice = createSlice({
  name: "users",
  initialState,
  reducers: {},
  extraReducers: (builder) => {
    builder
      .addCase(fetchUsers.pending, (state) => { state.loading = true; })
      .addCase(fetchUsers.fulfilled, (state, action) => {
        state.users = action.payload; // action.payload: User[]
        state.loading = false;
      })
      .addCase(fetchUsers.rejected, (state, action) => {
        state.error = action.payload ?? "Unknown error";
      });
  },
});

import { configureStore } from "@reduxjs/toolkit";
const store = configureStore({ reducer: { users: userSlice.reducer } });
export type RootState = ReturnType<typeof store.getState>;
export type AppDispatch = typeof store.dispatch;

import { useDispatch, useSelector, TypedUseSelectorHook } from "react-redux";
export const useAppDispatch = () => useDispatch<AppDispatch>();
export const useAppSelector: TypedUseSelectorHook<RootState> = useSelector;

const api = createApi({
  reducerPath: "api",
  baseQuery: fetchBaseQuery({ baseUrl: "/api" }),
  endpoints: (build) => ({
    getUser: build.query<User, string>({
      query: (id) => `/users/${id}`,
    }),
  }),
});
export const { useGetUserQuery } = api;

const selectUsers = (state: RootState): User[] => state.users.users;
const selectLoading = (state: RootState): boolean => state.users.loading;