Getting UID Reference for Firestore

Question

I'm trying to get a reference to a document's UID so I can use the document elsewhere in my project by it's UID. As per the documentation, I'm doing the following with AngularFire2 (v5):

var ref= this.afs.collection(placeToAdd).doc();

This gives me the following error: "Expected 1 arguments but got 0". It wants me to put an argument in the doc() method. So instead, I do:

var ref= this.afs.collection(placeToAdd).doc(thing);

then I set my Firebase object:

ref.set({
        item1: 'value 1',
        item2: 'value 2',
        item3: 'value 3'
      });

How do I get the ref's Firestore-generated UID now?

Answer 1

Figured it out:

let newUID = this.afs.createId();

Then create this firestore object at the location of newUID:

var ref= this.afs.collection(placeToAdd).doc(thing);

Answer 2

To clarify: there is two ways of inserting data in firestore. One recieves the uid from you.

db.collection(collection).doc(uid).set(data);

The other is adding the thocument but letting firestore generate the uid for you.

db.collection(collection).add(documentData)
.then(ref => {
    console.log("Document written with ID: ", ref.id);
});

It's important to note that both set and add return a promise of document ref, in case you want to use it and for error handling.

The documentation covers this in much more detail.