FirestoreDataConverter example doesn't work.

[marcusx2]

Operating System

macOS

Browser Version

Safari 16.5.2

Firebase SDK Version

10.4.0

Firebase SDK Product:

Firestore

Describe your project's tooling

index.html with source tag. Just javascript.

Describe the problem

This example does not work at all. The thrown error is TypeError: collection(db,'posts').withConverter(postConverter).doc is not a function. (In 'collection(db,'posts').withConverter(postConverter).doc()', 'collection(db,'posts').withConverter(postConverter).doc' is undefined.

The example is probably from the v8 version of the library. Can someone provide the v9 version of the example here until the docs get patched?

Steps and code to reproduce issue

class Post {
    constructor(title, author) { }

    toString() {
        return this.title + ', by ' + this.author;
    }
}

const postConverter = {
    toFirestore(post) {
        return { title: post.title, author: post.author };
    },
    fromFirestore(
        snapshot,
        options
    ) {
       const data = snapshot.data(options);
       return new Post(data.title, data.author);
    }
};

const db = getFirestore();
const postSnap = await collection(db,'posts').withConverter(postConverter).doc().get();

const post = postSnap.data();
if (post !== undefined) {
    post.title; // string
    post.toString(); // Should be defined
    post.someNonExistentProperty; // TS error
}

[marcusx2]

I tried modifying the code with the following (everything before is the same)

const col = await collection(db, 'posts').withConverter(postConverter);
const queryDocumentSnapshot = (await getDocs(col)).docs[0];
const doc = queryDocumentSnapshot.get(new FieldPath(queryDocumentSnapshot._key.path.segments));//undefined
console.log(queryDocumentSnapshot.data());//empty post

but apparently it's still wrong because I can't retrieve the document. This is what I have

[dconeybe]

@marcusx2 Thank you for pointing out this obvious issue with the documentation. I have opened a PR that re-writes the sample code. If you have some time, please take a look and let me know what you think. I added a "simple" converter and a "complex" converter sample: #7673

[marcusx2]

Looks good to me! I hope it gets merged sooner rather than later.