Search by pattern on Cloud Firestore collection

I'm trying to perform a filter by pattern over a Firestore collection. For exemple, in my Firestore database I have a brand called adidas. The user would have an search input, where typing "adi", "adid", "adida" or "adidas" returns the adidas document. I pointed out several solutions to do this :

1. Get all documents and perform a front-end filter

var brands = db.collection("brands");
filteredBrands = brands.filter((br) => br.name.includes("pattern"));

This solution is obviously not an option due to the Firestore pricing. Moreover it could be quite long to perform the request if the number of documents is high.

2. Use of Elasticsearch or Algolia

This could be interesting. However I think this is a bit overkill to add these solutions' support for only a pattern search, and also this can quickly become expensive.

3. Custom searchName field at object creation

So I had this solution : at document creation, create a field with an array of possible search patterns:

{
    ...
    "name":"adidas",
    "searchNames":[
        "adi",
        "adida",
        "adidas"
    ],
    ...
}

so that the document could be accessed with :

filteredBrands = db.collection("brands").where("searchNames", "array-contains", "pattern");

So I had several questions:

• What do you think about the pertinence and the efficiency of this 3rd solution? How far do you think this could be better than using a third party solution as Elasticsearch or Algolia?
• Do you have any other idea for performing pattern filter over a firestore collection?

IMHO, the first solution is definitely not an option. Downloading an entire collection to search for fields client-side isn't practical at all and is also very costly.

The second option is the best option considering the fact that will help you enable full-text search in your entire Cloud Firestore database. It's up to you to decide if it is worth using it or not.

What do you think about the pertinence and the efficiency of this 3rd solution?

Regarding the third solution, it might work but it implies that you create an array of possible search patterns even if the brand name is very long. As I see in your schema, you are adding the possible search patterns starting from the 3rd letter, which means that if someone is searching for ad, no result will be found. The downside of this solution is the fact that if you have a brand named Asics Tiger and the user is searching for Tig or Tige, you'll end up having again no results.

Do you have any other ideas for performing pattern filters over a Firestore collection?

If you are interested to get results only from a single word and using as a pattern the staring letters of the brand, I recommend you a better solution which is using a query that looks like this:

var brands = db.collection("brands");
brands.orderBy("name").startAt(searchName).endAt(searchName + "\uf8ff")

In this case, a search like a or ad will work perfectly fine. Besides that, there will be no need to create any other arrays. So there will be less document writing.

I have also written an article called:

• How to filter Firestore data cheaper?

That might also help.