Repro setup:

firebase init npm init npm install --save-dev typescript @types/node npx tsc --init add "build": "tsc" to package.json "runQueriesAgainstEmulator": "ts-node src/index.ts"

ADd tsconfig:

"include": ["src"], "exclude": ["node_modules"] Ensure firebase.json includes databases and indexes

To run

firebase emulators:start --project=ctfirestoreindexes

npm run build

npm run runQueriesAgainstEmulator

curl http://127.0.0.1:8080/emulator/v1/projects/ctfirestoreindexes:indexUsage?database=projects/ctfirestoreindexes/databases/\(default\)

Returns the following indexes:

{ "reports": [{ "index": { "name": "projects/ctfirestoreindexes/databases/(default)/collectionGroups/cities/indexes/", "queryScope": "COLLECTION", "fields": [{ "fieldPath": "name", "order": "ASCENDING" }, { "fieldPath": "state", "order": "ASCENDING" }, { "fieldPath": "name", "order": "ASCENDING" }] }, "numQueries": "6" }, { "index": { "name": "projects/ctfirestoreindexes/databases/(default)/collectionGroups/cities/indexes/", "queryScope": "COLLECTION", "fields": [{ "fieldPath": "state", "order": "ASCENDING" }, { "fieldPath": "population", "order": "ASCENDING" }, { "fieldPath": "name", "order": "ASCENDING" }] }, "numQueries": "2" }] }

to get already-deployed indexes:

firebase firestore:indexes

to deploy new indexes:

firebase deploy --only firestore:indexes

Transform emulator json to firestore.indexes.json in combine_indexes.ts

As a proof of concept run

curl http://127.0.0.1:8080/emulator/v1/projects/ctfirestoreindexes:indexUsage?database=projects/ctfirestoreindexes/databases/\(default\) > emulator_index_dump.json npm run convertTofirestoreIndexesJson

This will print out the new json file. Some additional work is required to replace firestore.indexes.json with the new json.

Transform notes in combine_indexes.ts

removes name convert "name" to "collectionGroup" by taking the collection ID flatten reports.index delete numQueries