State and Store in frontend codebases - Redux example - reducer

reducer.js

const initialState = { loading: true, users: [], error: undefined };

export function reducer(state = initialState, action) {
  console.log({ type: action.type, action });
  switch (action.type) {
    case "FETCH_USERS_SUCCEEDED":
      return {
        ...state,
        loading: false,
        users: action.payload.users.filter(
          (apiUser) => apiUser.type !== "ADMIN"
        )
      };

    case "FETCH_USERS_FAILED":
      return {
        ...state,
        loading: false,
        error: new Error("oops")
      };

    case "CREATE_USER_SUCCEEDED":
      return {
        ...state,
        users: [...state.users, action.payload.user]
      };

    case "CREATE_USER_FAILED":
      return {
        ...state,
        error: new Error("oops")
      };

    default: {
      return state;
    }
  }
}