thunk.js

module.exports = function simpleDispatchThunkMiddleware({ dispatch, getState }) {
  const newDispatch = (type, payload) => {
    if (typeof type === 'object') {
      dispatch(type);
    } else {
      dispatch({ type, payload });
    }
  };

  return next => action =>
    typeof action === 'function' ?
      action(newDispatch, getState) :
      next(action);
};