batchActionCreator.js

function batchActions(...actions) {
  return {
    type: 'BATCH_ACTIONS',
    actions: actions
  };
}

// usage
store.dispatch(
  batchActions(
    doSomething(),
    doSomethingElse()
  )
);

batchReducer.js

function enableBatching(reducer) {
  return function batchingReducer(state, action) {
    switch (action.type) {
    case 'BATCH_ACTIONS':
      return action.actions.reduce(reducer, state);
    default:
      return reducer(action, state);
    }
  }
}

// usage
let store = createStore(enableBatching(reducer));