设置后如何取回文件，firebase？

Question

How can I get back the documument ID after I set a new one?

I have a few attempts but here is my latest:

handleCreateCard = async (name, token) => {
    try {
        const new_card = await firestore()
          .collection('Cards')
          .doc()
          .set({
            user_id: user.uid,
            name: name,
            token: token,
          })
          .then(function(docRef) {
              console.log("Document written with ID: ", docRef.id);
          })
          .then(() => this.props.navigation.navigate("CardDetail", {cardId: 2}));

//              console.log("ATTEMPT !", handleCreateCard);
//              console.log("ATTEMPT 2", new_card);
        } catch (error) {
            console.log(error.toString(error));
        }
    }

The docRef line gets me the error:

Error: TypeError: null is not an object (evaluating 'docRef.id')

Logging handleCreateCard Error: ReferenceError: Can't find variable: handleCreateCard

Then the new_card : "THIS IS HERE undefined"

Tried doing:

.then(docRef => {
    console.log("Document written with ID: ", this.id); // also tried docRef.id
})

I get Document written with ID: undefined with docRef.id: TypeError: null is not an object (evaluating 'docRef.id')

The document is being created as well so not sure why it's not coming back

I've tried a handful of ways to do this and then also tried everything in here which some is above: Firestore - How to get document id after adding a document to a collection

Not sure why it's not working.

Any help?

Answer 1

As described in the API documentation, doc() with no parameters returns a DocumentReference immediately which already contains the ID.

const docRef = await firestore()
    .collection('Cards')
    .doc()
const id = docRef.id
docRef
    .set(...)
    .then(/* use the id here if you want */)