Separation of concerns in reducers working in same action

Question

I have the following normalized state shape that I want to implement.

{
    userAccounts: {
        byId: {
            "1234": {
                "id": "1234",
                "name": "Obi-wan",
                "gender": "Male",
                "age": 40
            },
            "4321": {
                "id": "4321",
                "name": "Padme",
                "gender": "Female",
                "age": 26
            },
            ...
        },
        allIds: ["1234", "4321", ...]
    }
}

This is the action that fetches data to get user accounts.

export const getAccounts = () => {
  return (dispatch) => {
    dispatch({type: GET_ACCOUNTS_REQUEST});
    return API.getAccountsList(session).then(
      (response) => {
        dispatch({
          type: GET_ACCOUNTS_SUCCESS,
          payload: response
        })
      },
      (error) => {
        ...
      }
    )
  };
};

The payload contains a key called accounts and this key contains an array among other non relevant fields.

payload: {
  accounts: [ { ... }, { ... } ],
  ...
}

My reducer waits for the action GET_ACCOUNTS_SUCCESS and I use combineReducers.

[GET_USERS_SUCCESS]: (state, action) => {
    return combineReducers({
      byId,
      allIds
    });
}

My current implementation of the reducer is like this:

const byId = (state, action) => {
  const { accounts } =  action.payload;
  const nextState = {
    byId: {},
    allIds: []
  };
  accounts.map(account => {
    nextState.byId[account.id] = {
      ...account
    };
    nextState.allIds = [
      ...nextState.allIds,
      account.id
    ]
  });
  return nextState;
};

I would like to separate this reducers into two to have better separation of concerns avoiding to do two maps.

Any idea?

Answer 1

You could create two new reducers listening to two new actions SET_ACCOUNT_BY_ID and SET_ACCOUNT_BY_ALL_IDS (as an example) which are dispatched by the GET_ACCOUNTS_SUCCESS action. When dispatching these two actions, you can pass in only the required data to them.