SQL function calling javascript function in a subquery does not work as expected

functest

create class buyer extends V
create class item extends V
create property item.quantity String
create class bought extends E

create vertex buyer
create vertex item set quantity=3

create edge from (select from buyer) to (select from item)

func1_javascript: input parameters A and B
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var my_a = parseInt(A);
var my_b = parseInt(B);

var sum = my_a + my_b;

return sum;

func2_sql (using subquery, does not give any results):
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select from (select expand(in(bought)) from item where quantity < func1_javascript($A,$B))

func3_sql (gives the expected results):
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select expand(in(bought)) from item where quantity < func1_javascript($A,$B)

if the parameter values are hardcoded, as below, then it gives the expected results
func4_sql (gives the expected results):
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select from (select expand(in(bought)) from item where quantity < func1_javascript(2,3))