code: function handleParamTree (api, field) {
              var params = api[field];
              // console.log(params)
              if ( params && params.length ) {
                  // console.log(params)
                  params.forEach(function (param, k) {
                      // callback.result -> ['callback', 'result']
                      var paramNames = param.field.split('.');
                      if ( paramNames && paramNames.length > 1 ) {
                          // 先清除之前的引用
                          params[k] = null;
                          handleParamBelong(field, paramNames, params, param)
                      }
                  });
                  // clean empty param
                  api[field] = params.filter(function (param) {
                      return param ? true : false;
                  });
              }
          }
docs: 参数层级化