$ $ ./1.js.pl
{"baz":function () { /* some JS here? */ },"foo":["bar","quz"]}
$ ./1.json.pl 
'false' expected, at character offset 7 (before "function () { /* som...") at ./1.json.pl line 7, <DATA> line 1.
$ cat 1.json.pl 
#!/usr/bin/perl -w
use 5.011;
use Data::Dumper;
use JSON;

my $json = <DATA>;
my $perl = decode_json $json;
print Dumper $perl;
__DATA__
{"baz":function () { /* some JS here? */ },"foo":["bar","quz"]}
$