simple variables in template literals about plv8 HOT 2 CLOSED

postgres=# CREATE OR REPLACE PROCEDURE public.testfn(a int) AS $$
  var b = 'foo';
  var c = {x: 'bar'};
  var s = `some things ${a} and ${b} and ${c} and ${c.x}`;
  plv8.elog(NOTICE, s, a, b, c.x);
$$
LANGUAGE plv8;
CREATE PROCEDURE
postgres=# call testfn(1234);
NOTICE:  some things 1234 and foo and [object Object] and bar 1234 foo bar
CALL