I have an existing kamailio config and I want to migrate to kemi. I want to know what is the equivalent of this code in kemi javascript ?

$avp(s:contact) = $hdr(Contact);
$avp(s:contact_fix) = $hdr(Contact);
avp_subst("$avp(s:contact_fix)", "/@([0-9]+).([0-9]+).([0-9]+).([0-9]+)/@$sel(cfg_get.kamailio.ss_ip)/gi");
remove_hf("Contact");
append_hf("Contact: $avp(s:contact_fix)\r\n");
t_on_reply("REG_FIX");

thanks for your attention.