Data model

One collection, in your database, under your connection. shorty never creates a second connection and never touches a collection you didn't give it.

The document

Field	Type
_id	ObjectId
userId	ObjectId → userRef	Indexed. A reference into a user system shorty does not own.
createdAt	Date	Indexed
updatedAt	Date

Indexes are yours to build

await pkg.model.createIndexes();

Call it once at boot, and await it in test setup. Mongoose builds indexes in the background, so a brand-new collection can serve a query before its index exists — and some queries throw rather than return empty when it doesn't. The symptom is "passes locally, fails in CI," which is a bad afternoon.

References out, never joins

shorty stores userId and never queries, joins against, or writes to your user collection. That is what makes purgeUser necessary rather than automatic — nothing in this package will ever notice a user disappearing on its own.

Using your own model

createShorty({ model: MyCompiledModel });

Bypasses the factory entirely. You own the schema, the indexes, and any drift from what the routes expect.