[Firestore] Typescript interface missing in the admin SDK for `FirestoreDataConverter`

[READ] Step 1: Are you in the right place?

Cloud Firestore support is provided by the @google-cloud/firestore library. Therefore the easiest and most efficient way to get Firestore issues resolved is by directly reporting them at the nodejs-firestore GitHub repo.

If you still think the problem is related to the code in this repository, then read on.

• For issues or feature requests related to the code in this repository file a Github issue.
• For general technical questions, post a question on StackOverflow with the firebase tag.
• For general Firebase discussion, use the firebase-talk google group.
• For help troubleshooting your application that does not fall under one of the above categories, reach out to the personalized Firebase support channel.

[REQUIRED] Step 2: Describe your environment

• Operating System version: Mac OS X
• Firebase SDK version: 7.24.0
• Firebase Product: Firestore
• Node.js version: 12.9.0
• NPM version: 6.14.8

[REQUIRED] Step 3: Describe the problem

Steps to reproduce:

Typescript interface missing in the admin SDK for FirestoreDataConveerter. As a result, I’m unable to use the withConverter method safely in my firestore queries.

Relevant Code:

firestore.collection(FireStoreCollections.Invoices).doc(invoice.id).withConverter().get();
// This does not work in typescript

Possible solution

I want to implement a data converter in typescript, somewhat like this

export const UserConverter: admin.firestore.FirestoreDataConverter<UserData> = {
	toFirestore(data: UserData): admin.firestore.DocumentData {
		const convertedDocumentData: admin.firestore.DocumentData = { ...data };
		return convertedDocumentData as UserData;
	},
	fromFirestore(
		snapshot: admin.firestore.QueryDocumentSnapshot,
		options: admin.firestore.SnapshotOptions
	): UserData {
		return snapshot.data(options) as UserData;
	}
};

To achieve this, we can export in interface from within the admin SDK’s types, somewhat like this

namespace admin {

  /**
   * An options object that configures the behavior of `set()` calls in
   * {@link firebase.firestore.DocumentReference.set DocumentReference}, {@link
   * firebase.firestore.WriteBatch.set WriteBatch} and {@link
   * firebase.firestore.Transaction.set Transaction}. These calls can be
   * configured to perform granular merges instead of overwriting the target
   * documents in their entirety by providing a `SetOptions` with `merge: true`.
   */
  export interface SetOptions {
    /**
     * Changes the behavior of a set() call to only replace the values specified
     * in its data argument. Fields omitted from the set() call remain
     * untouched.
     */
    readonly merge?: boolean;

    /**
     * Changes the behavior of set() calls to only replace the specified field
     * paths. Any field path that is not specified is ignored and remains
     * untouched.
     */
    readonly mergeFields?: (string | FieldPath)[];
  }

  /**
   * Converter used by `withConverter()` to transform user objects of type T
   * into Firestore data.
   *
   * Using the converter allows you to specify generic type arguments when
   * storing and retrieving objects from Firestore.
   *
   * @example
   * ```typescript
   * class Post {
   *   constructor(readonly title: string, readonly author: string) {}
   *
   *   toString(): string {
   *     return this.title + ', by ' + this.author;
   *   }
   * }
   *
   * const postConverter = {
   *   toFirestore(post: Post): firebase.firestore.DocumentData {
   *     return {title: post.title, author: post.author};
   *   },
   *   fromFirestore(
   *     snapshot: firebase.firestore.QueryDocumentSnapshot,
   *     options: firebase.firestore.SnapshotOptions
   *   ): Post {
   *     const data = snapshot.data(options)!;
   *     return new Post(data.title, data.author);
   *   }
   * };
   *
   * const postSnap = await firebase.firestore()
   *   .collection('posts')
   *   .withConverter(postConverter)
   *   .doc().get();
   * const post = postSnap.data();
   * if (post !== undefined) {
   *   post.title; // string
   *   post.toString(); // Should be defined
   *   post.someNonExistentProperty; // TS error
   * }
   * ```
   */
  export interface FirestoreDataConverter<T> {
    /**
     * Called by the Firestore SDK to convert a custom model object of type T
     * into a plain Javascript object (suitable for writing directly to the
     * Firestore database). To use `set()` with `merge` and `mergeFields`,
     * `toFirestore()` must be defined with `Partial<T>`.
     */
    toFirestore(modelObject: T): DocumentData;
    toFirestore(modelObject: Partial<T>, options: SetOptions): DocumentData;

    /**
     * Called by the Firestore SDK to convert Firestore data into an object of
     * type T. You can access your data by calling: `snapshot.data(options)`.
     *
     * @param snapshot A QueryDocumentSnapshot containing your data and metadata.
     * @param options The SnapshotOptions from the initial call to `data()`.
     */
    fromFirestore(snapshot: QueryDocumentSnapshot, options: SnapshotOptions): T;
  }

}

[schmidt-sebastian]

This might be the list:

BulkWriter
CollectionGroup
QueryPartition
GrpcStatus
UpdateData (type only)
Settings (type only)
BulkWriterOptions (type only)
Preconidtion (type only) 
ReadOptions (type only)
DocumentChangeType (type only)

[sagar7993]

@schmidt-sebastian @hiranya911 Thank you guys for the swift response 👏 Any idea when this can be released?