Can I set a UNIQUE constraint with a conditional?

I need to ensure uniqueness in an attribute but this attribute can be NULL. A simple

.unique

.unique

in my schema does not work in a sqlite database.

My goal is to achieve the equivalent of

CREATE UNIQUE INDEX unique_product_barcode_not_null ON products(barCode) WHERE barCode IS NOT NULL;

CREATE UNIQUE INDEX unique_product_barcode_not_null ON products(barCode) WHERE barCode IS NOT NULL;

using the Drizzle schema api.