Firebase 使用 orderByChild() 删除数据？

Question

When removing an item from my RTDB, my intention is to clean up user's likes if the item they like got removed.

With my data structure like so:

I am attempting to remove the nodes like this:

  const updates = {};

  //WORKS
  updates[`/strains/${title}/`] = null;
  updates[`/strainsMin/${title}/`] = null;

firebase
  .database()
  .ref('reviews')
  .orderByChild('s')
  .equalTo(title)
  .once('value', snapshot => {
    console.log(snapshot.val())
    snapshot.forEach(child => {
      console.log(child.key)
      //WORKS
      updates[`/reviews/${child.key}`] = null;
    });
  })
  .then(() => {
    firebase
    .database()
    .ref('userLikedStrains')
    .orderByChild(title)
    .equalTo(title)
    .once('value', snapshot => {
      console.log(snapshot.val() + 'likeylikeyyy')
      snapshot.forEach(child => {
        console.log(child.key)
        //DOESNT WORK
        updates[`/userLikedStrains/${child.key}/${title}`] = null;
      });
      firebase
      .database()
      .ref()
      .update(updates);
    })

For some reason this doesn't work. Is it because I am targeting a key (which is still a child?..)

I appreciate any help with this. Cheers.

Answer 1

The code you shared is not writing anything back to the database yet. For that you need to call update after the loop.

Something like:

let ref = firebase
    .database()
    .ref('userLikedStrains');

ref.orderByChild(title)
    .equalTo(title)
    .once('value', snapshot => {
      console.log(snapshot.val())
      snapshot.forEach(child => {
        console.log(child.key)
        updates[`/userLikedStrains/${child.key}/${title}`] = null;
      });
      ref.update(updates);
    })