PubSub - Javascript

• PubSub one of the property of a Meeting Class is used for messaging purpose for an ongoing meeting

Methods

publish()

• publish() is used to publish messages on a specified topic in the meeting.

• While publishing message, if you provide persist as true, then it will persist the message throughout the meeting and newly joined participant will get all old messages of a meeting, otherwise not.

Parameters

• topic :

  • type : String

• message :

  • type: String

• persist :

  • type : Boolean

• payload :

  • type : Object

Returns

• void

Example

const topic = "CHAT";

const _handlePublishChat = (message) => {
  //
  meeting.pubSub.publish(topic, message, { persist: true });
};

_handlePublishChat("Hello world!");

---

subscribe()

• subscribe() is used to subscribe a particular topic to get all the messages of that particular topic in the meeting. While publish() subscribe callback will be invoked.

Parameters

• topic :

  • type : String
  • Participants can listen to messages on that particular topic.

• callback :

  • type : function
  • in callback you will get newMessage object which contains Pubsub message data

Returns

• This will return old messages for this topic, if you passed persist to true while publish

• Array<message>

Example

const topic = "CHAT";

const _handleChat = (newMessage) => {
  //
  console.log(newMessage);
};

const _handleSubscribePubSub = async () => {
  let oldMessages = await meeting.pubSub.subscribe("CHAT", _handleChat);

  console.log(oldMessages);
};

---

unsubscribe()

• unsubscribe() is used to unsubscribe a particular topic on which you have subscribed priviously.

Parameters

• topic :

  • type : String
  • callback : function

• listener : function

Returns

• void

Example

const topic = "CHAT";

// same handler used for meeting.pubSub.subscribe()
const _handleChat = (newMessage) => {
  //
  console.log(newMessage);
};

const _handleUnsubscribePubSub = async () => {
  meeting.pubSub.unsubscribe("CHAT", _handleChat);
};

---

Pubsub message data

message

• type : String

• Message that has been published on the specific topic.

senderId

• type : String

• id of a sender who has published this message.

senderName

• type : String

• Name of a sender who has published this message.

timestamp

• type : DateTime

• Timestamp of when a message has been published.

topic

• type : String

• Name of the topic.

payload

• type : Object

• The additional data that you have send with message.