entities/message-type.enum.ts
export enum MessageTypeEnum {
register = "REGISTER",
invite = "INVITE",
ack = "ACK",
cancel = "CANCEL",
options = "OPTIONS",
prack = "PRACK",
subscribe = "SUBSCRIBE",
notify = "NOTIFY",
publish = "PUBLISH",
info = "INFO",
refer = "REFER",
message = "MESSAGE",
update = "UPDATE",
answer = "ANSWER",
reject = "REJECT",
iceCandidate = "ICE_CANDIDATE"
};