推送JavaScript后未更改Array的长度

Question

请帮助我解决怪异行为。我声明一个数组：   buildsArray = new Array（）;

并像这样在数组中添加对象项：

  var detailBuild = {
              id: elements.data.id,
              username: (elements.data.triggered.user) ? elements.data.triggered.user.username : "not user",
              project: (elements.data.buildType) ? elements.data.buildType.projectName : "not project",
              status: elements.data.status
            };
            buildsArray.push(detailBuild);

但是在推送之后，我的数组的length属性等于0。尽管

console.log (buildsArray);
console.log ("the length of buildsArray is " + buildsArray.length);

告诉我这个：

请告诉我我做错了什么，谢谢

完整代码：

 return promise.then((elements) => {
        console.log (elements.data.build);
        elements.data.build.forEach(element => {

          var detailpromise = httpService.getBuildDetail(element.href);
          detailpromise.then((elements) => {

            var detailBuild = {
              id: elements.data.id,
              username: (elements.data.triggered.user) ? elements.data.triggered.user.username : "not user",
              project: (elements.data.buildType) ? elements.data.buildType.projectName : "not project",
              status: elements.data.status
            };
            buildsArray.push(detailBuild);
            var item = buildsGroupingByProject.find(element => element.projectName === detailBuild.project);
            (item === undefined) ?
            buildsGroupingByProject.push({
                projectName: detailBuild.project,
                buildArrays: new Array(detailBuild)
              })
              :
              item.buildArrays.push(detailBuild);

          });
        });
        console.log (buildsArray);
        console.log ("the length of buildsArray is " + buildsArray.length);
        return buildsGroupingByProject;
      });
    }