Recently firebase has released new Extensions (Search with Algolia) that allow developers to upload firestore records to Algolia for full text search without having to write their own firebase functions.
Here is how I set up Search with Algolia to upload the contents of title and create_at to Algolia when there are updates to the firestore post collection.
The Extensions is essentially a firebase function, so after you have successfully installed extensions, you will find that the firebase function will have an additional function called ext-firestore-algolia-search-executeIndexOperation by default.
You can use any of the functions that the firebase function has, such as logging.
As shown, when extensions are triggered there will be logging.
Tips
The timestamp of the Firestore data type looks like this in Algolia, it is not an ISO 8601 timestamp, so it cannot be used directly in Algolia for sorting
If you want to sort by created_at, you need to sort by created_at._seconds
