Firebase + Redux Saga

Actions.jsx

export const actionTypes = {
  FETCH_USER_REQUEST: "USER/FETCH",
  FETCH_USER_REQUEST_ERROR: "USER/FETCH_ERROR",

  USER_CHANGED: "USER/CHANGED",
  LOGOUT: "LOGOUT",
  ACCESS_TOKEN_CHANGED: "ACCESS_TOKEN/CHANGED"
};

Saga.jsx

function* startListener() {
  // #1
  const channel = new eventChannel(emiter => {
    const listener = database.ref("todos").on("value", snapshot => {
      emiter({ data: snapshot.val() || {} });
    });

    // #2
    return () => {
      listener.off();
    };
  });

  // #3
  while (true) {
    const { data } = yield take(channel);
    // #4
    yield put(actionsCreators.updateList(data));
  }
}

export default function* root() {
  yield fork(startListener);
}