CREATE FUNCTION valid_arraybuffer_bytea(len integer) RETURNS bytea
LANGUAGE plv8 IMMUTABLE STRICT
AS $$
  return new ArrayBuffer(len);
$$;
SELECT length(valid_arraybuffer_bytea(20));
 length 
--------
     20
(1 row)

CREATE FUNCTION valid_int8array_bytea(len integer) RETURNS bytea
LANGUAGE plv8 IMMUTABLE STRICT
AS $$
  return new Int8Array(len);
$$;
SELECT length(valid_int8array_bytea(20));
 length 
--------
     20
(1 row)

CREATE FUNCTION valid_int16array_bytea(len integer) RETURNS bytea
LANGUAGE plv8 IMMUTABLE STRICT
AS $$
  return new Int16Array(len);
$$;
SELECT length(valid_int16array_bytea(20));
 length 
--------
     40
(1 row)