將多個對象合並成一個數組的方法

   console.log(res);
   console.log(res.data.activities);//這是多個對象
        var activityList = [];
        const activityData = res.data.activities;
        for (const key in activityData) {
          if (activityData[key]) {
            activityList = activityList.concat(activityData[key]);
          }
        }
   console.log(activityList);//合並后的數組