javascript - 如何将 Firebase 中的节点(对象)复制到另一个节点？

Question

我在 Firebase 中有一个名为“Events”的节点。它由子对象组成，例如:地址、描述、经度、纬度。在用户删除事件节点之前，我想将其复制到同一数据库中名为 eventsDeleted 的节点。

这是删除节点的代码:

removeEvent(eventId, groupId) {

  return new Promise((resolve, reject)=> {

    this.eventRef.child(groupId).child(eventId).remove();
    resolve();

  });

}

这是创建节点的代码:

addEvent(data:any) {
    console.log('Form data', data.group);

    let localEventRef = firebase.database().ref('events').child(data.group.split(',')[1]);
    let storageRef = firebase.storage().ref();
    let file = data.image;
    let uploadTask = storageRef.child('eventImages/' + UuidGenerator.generateUUID()).put(file);
    uploadTask.on('state_changed', function (snapshot) {

    }, function (error) {
        // Handle unsuccessful uploads
        console.error(error);
    }, function () {
        // Handle successful uploads on complete
        let downloadURL = uploadTask.snapshot.downloadURL;
        let keyOfNewEvent = localEventRef.push(
            new Event(
                null,
                firebase.app().auth().currentUser.uid,

                data.description,


                data.location.address,
                0

            )
        ).key;
        localEventRef.child(keyOfNewEvent).update({eventId: keyOfNewEvent});
    });


}

不用介意上传图像的代码。我只需要一种方法来复制整个节点(如果可能)，然后将其粘贴到数据库中的某个位置。提前致谢。

Answer 1

当用户单击删除时，请确保获取正在删除的对象，如果您要在数据库中查询该对象，您可以使用 .once 来检索该对象，否则您可以直接跳转到removeEvent函数。

localEventRef.child(keyOfEvent).once("value", function(snapshot) {
 //one data is returned, you can then call the removeEvent fn

  let eventToBeRemoved = snapshot.val();
  //assuming you have the eventid, groupid then. 
  removeEvent(eventId, groupId, eventToBeRemoved);
});

removeEvent(eventId, groupId, eventObjectToBeRemoved) {
//firebase 3.x comes with a promise method

    firebase.database().ref('eventsDeleted/' + groupId + '/' + eventId )
      .set({...eventObjectToBeRemoved})
      .then(function () { 
        eventRef.child(groupId).child(eventId).remove();//you can now remove
      })
      .catch(function (error) {
        console.error("error occured trying to add to deletedEvents", error);
      });
    });
}