Question

我正在添加用户地理位置，并且想在将数据推送到数组之前检查snapShot.data（）。location.geopoint是否为null，但是我仍然收到以下错误：

ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'geopoint' of undefined
TypeError: Cannot read property 'geopoint' of undefined

这是实际的代码吗？

query.get()
            .then(list => {
              list.forEach(snapShot => {
                let userLat = (snapShot.data().location.geopoint.latitude > 0) ? snapShot.data().location.geopoint.latitude : 0;
                let userLong = (snapShot.data().location.geopoint.longitude > 0) ? snapShot.data().location.geopoint.longitude : 0;

                console.log('use lat long', userLat, userLong);

                let distance = this.geo.distance(this.geo.point(myLat, myLong), this.geo.point(userLat, userLong));
                if (distance <= this.userSettings.distance.upper) {
                  this.userInfo.push({
                    userId: snapShot.data().userId,
                    displayName: snapShot.data().displayName,
                  });
                }
              });
            })

鉴于它抱怨我添加的实际null检查，我如何在geopoint中检查null值：

            let userLat = (snapShot.data().location.geopoint.latitude > 0) ? snapShot.data().location.geopoint.latitude : 0;

Answer 1

您可以使用snapshot.get(fieldPath) API（docs）并执行以下操作：

let userLat = 0;
let userLong = 0;

if (snapShot.get("location.geopoint")) {
  userLat = snapShot.get("location.geopoint").latitude;
  userLong = snapShot.get("location.geopoint").longitude;
}

如何在Geopoint字段上检查Firebase data（）的空值

1 个答案: