text: /**
   * redux-thunk 源码
   * 增强了 dispatch 能力，dispatch 从 只能接受 object 变成也可结束 function
   */
  function createThunkMiddleware(extraArgument) {
    return ({ dispatch, getState }) => next => action => {
      if (typeof action === 'function') {
        return action(dispatch, getState, extraArgument);
      }
      return next(action);
    };
  }
  
  const thunk = createThunkMiddleware();
  thunk.withExtraArgument = createThunkMiddleware;
  
  export default thunk;
  