plpgsql: filter new value's array field

I have a database function that goes like:

declare
    ftl sometype[] := /*filter new.items that has field x as True*/;
begin
  IF pg_trigger_depth() = 1 then

declare
    ftl sometype[] := /*filter new.items that has field x as True*/;
begin
  IF pg_trigger_depth() = 1 then

how can I filter

new.items

new.items

? is that a thing in postgres? I tried

SELECT

SELECT

ing from

new.items

new.items

but that didn't work.

plpgsql: filter new value's array field - Supabase