createStoreSection.js

import _ from 'lodash-fp';
import { createFunctionsChain, groupProperties } from 'utils/collection';

export default function createStoreSection(prefix, samples) {
  if (samples.some(sample => !sample)) {
    throw new TypeError('Sample cant be empty');
  }

  const path = (suffix) => `${prefix}/${suffix}`;

  const reducersSource = groupProperties( _.map('reducers', samples) );

  const initialState = samples.reduce(
    (state, sample) => ({ ...state, ...sample.initialState }), {}
  );

  const reducersMap = Object.keys(reducersSource)
    .reduce((result, key) => {
      result[path(key)] = createFunctionsChain(reducersSource[key]);
      return result;
    }, {});

  const payload = (actionName, args) => {
    return samples.reduce( (result, value) =>
        value.payloads && value.payloads[actionName]
          ? { ...result, ...value.payloads[actionName](args, initialState) }
          : result
      , {});
  };

  const createAction = (actionName, args) => ({
    type: path(actionName),
    payload: payload(actionName, args)
  });

  return { initialState, reducersMap, createAction };
}