code: function findHandlers(arr, name, callback) {
          var ret = [];
  
          each(arr, function (handler) {
              if (handler &&
                  (!name || handler.e === name) &&
                  (!callback || handler.cb === callback || handler.cb._cb === callback)) {
                  ret.push(handler);
              }
          });
  
          return ret;
      }
docs: 根据条件过滤出事件handlers.