Firestore Getting documents id from collection

问题:

I'm trying to retrieve my documents with id but can't figure it out.
Currently I retrieve my documents like this :

const racesCollection: AngularFirestoreCollection<Races> = this.afs.collection('races');
return racesCollection.valueChanges();

I do get my documents list perfectly, however there is no doc id with them.

How can I retrieve it for each document ?

回答1:

To obtain the id of the documents in a collection, you must use snapshotChanges()

this.shirtCollection = afs.collection<Shirt>('shirts');
// .snapshotChanges() returns a DocumentChangeAction[], which contains
// a lot of information about "what happened" with each change. If you want to
// get the data and the id use the map operator.
this.shirts = this.shirtCollection.snapshotChanges().map(actions => {
  return actions.map(a => {
    const data = a.payload.doc.data() as Shirt;
    const id = a.payload.doc.id;
    return { id, ...data };
  });
});

Documentation https://github.com/angular/angularfire2/blob/7eb3e51022c7381dfc94ffb9e12555065f060639/docs/firestore/collections.md#example

回答2:

I've finally found the solution. Victor was close with the doc data.

const racesCollection: AngularFirestoreCollection<Race>;
return racesCollection.snapshotChanges().map(actions => {       
  return actions.map(a => {
    const data = a.payload.doc.data() as Race;
    data.id = a.payload.doc.id;
    return data;
  });
});

ValueChanges() doesn't include metadata, therefor we must use SnapshotChanges() when we require the document id and then map it properly as stated here https://github.com/angular/angularfire2/blob/master/docs/firestore/collections.md

回答3:

For angular6+

this.shirtCollection = afs.collection<Shirt>('shirts');
this.shirts = this.shirtCollection.snapshotChanges().pipe(
    map(actions => {
    return actions.map(a => {
        const data = a.payload.doc.data() as Shirt;
        const id = a.payload.doc.id;
        return { id, ...data };
    });
    })
);

回答4:

For angular 8 and Firebase 6 you can use the option id field

      getAllDocs() {
           const ref = this.db.collection('items');
           return ref.valueChanges({idField: 'customIdName'});
      }

this adds the Id of the document on the object with a specified key (customIdName)

回答5:

doc.id gets the UID.

Combine with the rest of the data for one object like so:

Object.assign({ uid: doc.id }, doc.data())

回答6:

Can get ID before add documents in database:

var idBefore =  this.afs.createId();
console.log(idBefore);

回答7:

Have tried this!

colWithIds$<T>(ref: CollectionPredicate<T>, queryFn?): Observable<any[]> {
    return this.col(ref, queryFn).snapshotChanges().pipe(
    map(actions => {
      return actions.map(a => {
        const data = a.payload.doc.data();
        const id = a.payload.doc.id;
        return { id, ...data };
      });
    }));
  }

but I run into this error

[ts] Spread types may only be created from object types. const data: T

回答8:

Since you are using angularFire, it doesn't make any sense if you are going back to default firebase methods for your implementation. AngularFire itself has the proper mechanisms implemented. Just have to use it.

valueChanges() method of angularFire provides an overload for getting the ID of each document of the collection by simply adding a object as a parameter to the method.

valueChanges({ idField: 'id' })

Here 'idField' must be same as it is. 'id' can be anything that you want your document IDs to be called.

Then the each document object on the returned array will look like this.

{
  field1 = <field1 value>,
  field2 = <field2 value>,
  ..
  id = 'whatEverTheDocumentIdWas'
}

Then you can easily get the document ID by referencing to the field that you named.

AngularFire 5.2.0