docs: function mkdir(dirpath, dirname) {
      //判断是否是第一次调用  
      if (typeof dirname === "undefined") {
          if (fs.existsSync(dirpath)) {
              return;
          } else {
              mkdir(dirpath, path.dirname(dirpath));
          }
      } else {
          //判断第二个参数是否正常，避免调用时传入错误参数  
          if (dirname !== path.dirname(dirpath)) {
              mkdir(dirpath);
              return;
          }
          if (fs.existsSync(dirname)) {
              fs.mkdirSync(dirpath)
          } else {
              mkdir(dirname, path.dirname(dirname));
              fs.mkdirSync(dirpath);
          }
      }
  }