Objection.js: Possible optimization with first() method

[sgangwisch]

Looking through the source code I noticed that the first query method pulls down the entire dataset and then returns the first element in the array. A possible optimization to this would be to automatically append limit(1) if not present in order to limit the returned dataset to just one record. Thoughts?

[fl0w]

That's exactly what knex.QueryBuilder#first does though. Does objection.QueryBuilder#first have a different use case?

[koskimas]

The first method was meant to be more like a shortcut to .then(_.first) but maybe we could add the limit(1) there without breaking too many things. We should try to be compatible with knex as much as possible.

[koskimas]

This would break join based eager queries as well as any usage with update and insert* methods. Maybe we shouldn't do this. I'll add a mention to the documentation that this doesn't modify the database query. limit(1) needs to be used in addition to get the performance benefits.

[vladshcherbin]

Also curious about this one, when using first(), limit is not added to the query, so basically what you have to do is:

const user = await User.query().where('id', id).limit(1).first()

Looks a bit weird and is not mentioned in the docs. (or maybe I didn't find)

Maybe something has changed since issue was created so limit can be added by default?