code: function emit(resolver) {
          var items = resolver.status === STATUS.FULFILLED
              ? resolver.fulfillList
              : resolver.rejectList;
  
          emitGlobalEvent(resolver);
  
          if (!items.length) {
              return;
          }
  
          // 触发注册的回调函数必须
          // 在状态改变完成后
          // see #2.2.2 #2.2.3 #2.2.4
          Resolver.nextTick(
              function () {
                  var item;
                  while (item = items.shift()) {
                      item(resolver.data);
                  }
              }
          );
      }
docs: 触发resolver回调函数
  根据状态，执行resolver的回调函数
  
  @inner
  @param {Object} resolver resolver对象