loading_reducer.js

const loadingReducer = (state = {}, action) => {
  const { type } = action;
  const matches = /(.*)_(START|SUCCESS|FAIL)/.exec(type);

  // not a *_START / *_SUCCESS /  *_FAILURE actions, so we ignore them
  if (!matches) return state;

  const [, requestName, requestState] = matches;
  return {
    ...state,
    // Store whether a request is happening at the moment or not
    // e.g. will be true when receiving GET_TODOS_REQUEST
    //      and false when receiving GET_TODOS_SUCCESS / GET_TODOS_FAILURE
    [requestName]: requestState === 'START',
  };
};

export default loadingReducer;

loading_selector.js

import _ from 'lodash';
export const createLoadingSelector = (actions) => (state) => {
  // returns true only when all actions is not loading
  return _(actions)
    .some((action) => _.get(state, `loading.${action}`));
};