Last Updated: 3/9/2026
Not null
Sometimes you can be sure something’s not null, but Kysely isn’t able to infer
it. For example calling where('last_name', 'is not', null) doesn’t make
last_name not null in the result type, but unless you have other where statements
you can be sure it’s never null.
Kysely has a couple of helpers for dealing with these cases: $notNull() and $narrowType.
Both are used in the following example:
import { notNull } from ’./0051-not-null’
:::info[More examples] The API documentation is packed with examples. The API docs are hosted here , but you can access the same documentation by hovering over functions/methods/classes in your IDE. The examples are always just one hover away!
For example, check out these sections: