epicHelpers.js

import 'rxjs';
import { Observable } from 'rxjs';

Observable.prototype.debug = function(_message) {
  const message = `EpicDebug: ${_message}`;

  return this.do(
        function(next) {
          if (__DEV__) {
            console.log(message, next);
          }
        },
        function(err) {
          if (__DEV__) {
            console.error('ERROR >>> ', message, err);
          }
        },
        function() {
          if (__DEV__) {
            console.log('Completed.', message);
          }
        }
    );
};

const debugEpic = debugName => epic => (...args) =>
  epic(...args)
  .catch((error, source) => {
    console.info(`${debugName}: caught an error.`, error, source);
    setTimeout(() => {
      throw error;
    }, 0);
    return source;
  })
  .finally(() =>
    console.info(`${debugName}: epic exited.`, args)
  );

export const wrapEpics = (epicObj, debugName = 'root') => {
  if (typeof epicObj === 'function') {
    return debugEpic(debugName)(epicObj);
  }

  return combineEpics(
    ...Object
    .entries(epicObj)
    .map(([name, epics]) => wrapEpics(epics, `${debugName}/${name}`))
    .map(debugEpic(debugName))
  );
};

epics.js

import { wrapEpics } from './epicHelpers';

import * as reducer1Epics from './reducer1/epics';
import * as reducer2Epics from './reducer2/epics';

export default wrapEpics({
  reducer1Epics,
  reducer2Epics,
});

reducer1epics.js

export const exampleEpic = epic$ => ...