CREATE FUNCTION return_void() RETURNS void AS $$ $$ LANGUAGE pljs;
SELECT return_void();
 return_void 
-------------
 
(1 row)

CREATE FUNCTION return_null() RETURNS text AS $$ return null; $$ LANGUAGE pljs;
SELECT r, r IS NULL AS isnull FROM return_null() AS r;
 r | isnull 
---+--------
   | t
(1 row)

-- TYPE CONVERTIONS
CREATE FUNCTION int2_to_int4(x int2) RETURNS int4 AS $$ return x; $$ LANGUAGE pljs;
SELECT int2_to_int4(24::int2);
 int2_to_int4 
--------------
           24
(1 row)

CREATE FUNCTION int4_to_int2(x int4) RETURNS int2 AS $$ return x; $$ LANGUAGE pljs;
SELECT int4_to_int2(42);
 int4_to_int2 
--------------
           42
(1 row)

CREATE FUNCTION int4_to_int8(x int4) RETURNS int8 AS $$ return x; $$ LANGUAGE pljs;
SELECT int4_to_int8(48);
 int4_to_int8 
--------------
           48
(1 row)

CREATE FUNCTION int8_to_int4(x int8) RETURNS int4 AS $$ return x; $$ LANGUAGE pljs;
SELECT int8_to_int4(84);
 int8_to_int4 
--------------
           84
(1 row)

CREATE FUNCTION float8_to_numeric(x float8) RETURNS numeric AS $$ return x; $$ LANGUAGE pljs;
SELECT float8_to_numeric(1.5);
 float8_to_numeric 
-------------------
               1.5
(1 row)

CREATE FUNCTION numeric_to_int8(x numeric) RETURNS int8 AS $$ return x; $$ LANGUAGE pljs;
SELECT numeric_to_int8(1234.56);
 numeric_to_int8 
-----------------
            1234
(1 row)

CREATE FUNCTION int4_to_text(x int4) RETURNS text AS $$ return x; $$ LANGUAGE pljs;
SELECT int4_to_text(123);
 int4_to_text 
--------------
 123
(1 row)

CREATE FUNCTION text_to_int4(x text) RETURNS int4 AS $$ return x; $$ LANGUAGE pljs;
SELECT text_to_int4('123');
 text_to_int4 
--------------
          123
(1 row)

SELECT text_to_int4('abc');
 text_to_int4 
--------------
            0
(1 row)

-- ARRAYS
CREATE FUNCTION return_array() RETURNS TEXT[] AS $$ return ["foo", "bar"]; $$LANGUAGE pljs;
SELECT return_array();
 return_array 
--------------
 {foo,bar}
(1 row)

-- BigInt
-- a BigInt that will work on any value
CREATE OR REPLACE FUNCTION bigint_working(val BIGINT)
   RETURNS BIGINT AS $$
    return val - 1n;
   $$ LANGUAGE pljs 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 pljs STABLE STRICT;
SELECT bigint_failing(9223372036854775807);
ERROR:  execution error
DETAIL:  TypeError: cannot convert bigint to number
    at bigint_failing (<function>:3:16)

-- BigInt as Numeric
CREATE OR REPLACE FUNCTION bigint_numeric(a INT8, b INT8)
   RETURNS NUMERIC AS $$
    return a ** b;
   $$ LANGUAGE pljs STABLE STRICT;
SELECT bigint_numeric(20, 200);
                                                                                                                            bigint_numeric                                                                                                                             
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 160693804425899027554196209234116260252220299378279283530137600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
(1 row)

-- ENUM type
CREATE TYPE status AS ENUM ('active', 'inactive', 'pending');
CREATE FUNCTION enum_echo(s status) returns status AS $$
  return s;
$$ LANGUAGE pljs;
SELECT enum_echo('active');
 enum_echo 
-----------
 active
(1 row)

-- Custom type
CREATE EXTENSION ltree;
CREATE FUNCTION ltree_echo(l ltree) RETURNS ltree AS $$
  return l;
$$ LANGUAGE pljs;
SELECT ltree_echo('1.2.3'::ltree);
 ltree_echo 
------------
 1.2.3
(1 row)