CODEWITHSUNDEEP
iosswiftfirebasegoogle-cloud-firestore
bhr
bhr

Reputation: 2337

How to sort Firestore query results with whereField is using arrayContainsAny and in

The Problem

I'm looking for a way to sort Firestore query results that use arrayContainsAny or in for the whereField clause.

Every time I set up a paginated query and process the first batch, I get different results back in different order.

The Firestore documentation says

You cannot order your query by any field included in an equality (=) or in clause.

I've tried ordering by name field and first ordering by categories and then other fields. Whatever I enter does not seem to be used for the query.

Example

Let's imagine the following data structure:

brands/
    chiquita/
        products/
            banana: {
                name: "Banana",
                categories: ["fruits", "berries"]
            }
    365organic/
        products/
            romaine: {
                name: "Romaine Lettuce",
                categories: ["lettuce", "vegetables"]
            }
    mars/
        products/
            snickers: {
                name: "Snickers",
                categories: ["chocolate bars"]
            }

Here's my Firestore query in swift:

var query = self.database.collectionGroup("products")
    .whereField("categories", arrayContainsAny: ["fruits", "vegetables"])
    .orderBy("name")
    .limit(to: 25)

    // lastSnapshot is the last doc's snapshot or nil if called the first time
    if let lastSnapshot = lastSnapshot { 
        query = query.start(afterDocument: lastSnapshot)
    }

Upvotes: 0

Views: 313

Answers (1)

bhr
bhr

Reputation: 2337

After digging deeper through the client logic I found an issue that caused the sorting to not be applied client-side.

After fixing that I'm getting back the items sorted consistently!

Upvotes: 1

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