-- BigInt precedures
-- a BigInt that will work on any value
CREATE OR REPLACE FUNCTION bigint_working(val BIGINT)
   RETURNS BIGINT AS $$
    return val - 1n;
   $$ LANGUAGE plv8 STABLE STRICT;
SELECT bigint_working(9223372036854775807);
   bigint_working    
---------------------
 9223372036854775806
(1 row)

SELECT bigint_working(32);
 bigint_working 
----------------
             31
(1 row)

-- a BigInt that will fail on any value
CREATE OR REPLACE FUNCTION bigint_failing(val BIGINT)
   RETURNS BIGINT AS $$
    return val - 1;
   $$ LANGUAGE plv8 STABLE STRICT;
SELECT bigint_failing(9223372036854775807);
ERROR:  TypeError: Cannot mix BigInt and other types, use explicit conversions
CONTEXT:  bigint_failing() LINE 2:     return val - 1;
-- BigInt as Numeric
CREATE OR REPLACE FUNCTION bigint_numeric(a INT8, b INT8)
   RETURNS NUMERIC AS $$
    return a ** b;
   $$ LANGUAGE plv8 STABLE STRICT;
SELECT bigint_numeric(20, 200);
                                                                                                                            bigint_numeric                                                                                                                             
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 160693804425899027554196209234116260252220299378279283530137600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
(1 row)