Avatar stack
Avatar stacks are the most common way of showing the online status of members in an application by displaying an avatar for each member. Events are emitted whenever a member enters or leaves a space, or updates their profile data. Additional information can also be provided, such as a profile picture and email address.
Subscribe to the space.members namespace in order to keep your avatar stack updated in realtime.
Event types
The following four event types are emitted by members:
enter- A new member has entered the space. The member has either entered explicitly by calling
space.enter(), or has attempted to update their profile data before entering a space, which will instead emit anenterevent. updateProfile- A member has updated their profile data by calling
space.updateProfileData(). leave- A member has left the space. The member has either left explicitly by calling
space.leave(), or has abruptly disconnected and not re-established a connection within 15 seconds. remove- A member has been removed from the members list after the
offlineTimeoutperiod has elapsed. This enables members to appear greyed out in the avatar stack to indicate that they recently left for the period of time between theirleaveandremoveevents. update- This event is emitted whenever any one of the above events is emitted.
Subscribe to member events
Subscribe to members’ online status and profile updates by registering a listener. Member events are emitted whenever a member enters or leaves the space, or updates their profile data. Use the subscribe() method on the members object of a space to receive updates.
The following is an example of subscribing to the different member event types:
// Subscribe to member enters in a space
space.members.subscribe('enter', (memberUpdate) => {
console.log(memberUpdate);
});
// Subscribe to member profile data updates in a space
space.members.subscribe('updateProfile', (memberUpdate) => {
console.log(memberUpdate);
});
// Subscribe to member leaves in a space
space.members.subscribe('leave', (memberUpdate) => {
console.log(memberUpdate);
});
// Subscribe to member removals in a space
space.members.subscribe('remove', (memberUpdate) => {
console.log(memberUpdate);
});
CopyCopied!It’s also possible to subscribe to multiple event types with the same listener by using an array:
space.members.subscribe(['enter', 'updateProfile'], (memberUpdate) => {
console.log(memberUpdate);
});
CopyCopied!Or subscribe to all event types:
space.members.subscribe('update', (memberUpdate) => {
console.log(memberUpdate);
});
CopyCopied!The following is an example payload of a member event. The lastEvent.name describes which event type a payload relates to.
{
"clientId": "clemons#142",
"connectionId": "hd9743gjDc",
"isConnected": true,
"lastEvent": {
"name": "enter",
"timestamp": 1677595689759
},
"location": null,
"profileData": {
"username": "Claire Lemons",
"avatar": "https://slides-internal.com/users/clemons.png"
}
}
CopyCopied!The following are the properties of a member event payload:
| Property | Description | Type |
|---|---|---|
| clientId | The client identifier for the member. | String |
| connectionId | The unique identifier of the member’s connection. | String |
| isConnected | Whether the member is connected to Ably or not. | Boolean |
| profileData | The optional profile data associated with the member. | Object |
| location | The current location of the member. Will be null for enter, leave and remove events. | Object |
| lastEvent.name | The most recent event emitted by the member. | String |
| lastEvent.timestamp | The timestamp of the most recently emitted event. | Number |
Unsubscribe from member events
Unsubscribe from member events to remove previously registered listeners.
The following is an example of removing a listener for one member event type:
space.members.unsubscribe('enter', listener);
CopyCopied!It’s also possible to remove listeners for multiple member event types:
space.members.unsubscribe(['enter', 'leave'], listener);
CopyCopied!Or remove all listeners:
space.members.unsubscribe();
CopyCopied!Retrieve members
Space membership can be retrieved in one-off calls. These are local calls and retrieve the membership retained in memory by the SDK. One-off calls to retrieve membership can be used for operations such as displaying a member’s own profile data to them, or retrieving a list of all other members to use to update their profile data.
The following is an example of retrieving a member’s own member object:
const myMemberInfo = await space.members.getSelf();
CopyCopied!The following is an example payload returned by space.members.getSelf()
{
"clientId": "clemons#142",
"connectionId": "hd9743gjDc",
"isConnected": true,
"lastEvent": {
"name": "enter",
"timestamp": 1677595689759
},
"location": null,
"profileData": {
"username": "Claire Lemons",
"avatar": "https://slides-internal.com/users/clemons.png"
}
}
CopyCopied!The following is an example of retrieving an array of member objects for all members other than the member themselves. Ths includes members that have recently left the space, but have not yet been removed.
const othersMemberInfo = await space.members.getOthers();
CopyCopied!The following is an example payload returned by space.members.getOthers()
[
{
"clientId": "torange#1",
"connectionId": "tt7233ghUa",
"isConnected": true,
"lastEvent": {
"name": "enter",
"timestamp": 167759566354
},
"location": null,
"profileData": {
"username": "Tara Orange",
"avatar": "https://slides-internal.com/users/torange.png"
}
},
{
"clientId": "amint#5",
"connectionId": "hg35a4fgjAs",
"isConnected": true,
"lastEvent": {
"name": "update",
"timestamp": 173459567340
},
"location": null,
"profileData": {
"username": "Arit Mint",
"avatar": "https://slides-internal.com/users/amint.png"
}
}
]
CopyCopied!The following is an example of retrieving an array of all member objects, including the member themselves. Ths includes members that have recently left the space, but have not yet been removed.
const allMembers = await space.members.getAll();
CopyCopied!The following is an example payload returned by space.members.getAll()
[
{
"clientId": "clemons#142",
"connectionId": "hd9743gjDc",
"isConnected": false,
"lastEvent": {
"name": "enter",
"timestamp": 1677595689759
},
"location": null,
"profileData": {
"username": "Claire Lemons",
"avatar": "https://slides-internal.com/users/clemons.png"
}
},
{
"clientId": "amint#5",
"connectionId": "hg35a4fgjAs",
"isConnected": true,
"lastEvent": {
"name": "update",
"timestamp": 173459567340
},
"location": null,
"profileData": {
"username": "Arit Mint",
"avatar": "https://slides-internal.com/users/amint.png"
}
},
{
"clientId": "torange#1",
"connectionId": "tt7233ghUa",
"isConnected": true,
"lastEvent": {
"name": "enter",
"timestamp": 167759566354
},
"location": null,
"profileData": {
"username": "Tara Orange",
"avatar": "https://slides-internal.com/users/torange.png"
}
}
]
CopyCopied!Example usage
The following is an example of the steps involved in implementing an avatar stack.
import Spaces from '@ably/spaces';
import { Realtime } from 'ably';
// Import your custom logic for handling avatar stack UI updates
import { renderAvatars } from '/src/own-logic';
// Create an Ably client
const client = new Realtime.Promise({ authUrl: '<authEndpoint>', clientId: '<clientId>' });
// Initialize the Spaces SDK using the Ably client
const spaces = new Spaces(client);
// Create a new space and set the offlineTimeout period to 3 minutes
const space = await spaces.get('board-presentation', { offlineTimeout: 180_000});
// Enter the space to become a member, passing a nickname
await space.enter({ name: 'Kyle' });
// Listen to all member changes within the space
space.members.subscribe('update', async (member) => {
// Use getOthers() to filter and update the state of all avatars except the member's own
const otherMembers = await space.members.getOthers();
renderAvatars(otherMembers);
});
// Listen to 'leave' events to update the avatars of those members who have left the space
space.members.subscribe('leave', (member) => {
renderAvatars('memberHasLeft', member);
});
// Listen to 'remove' events to remove members from the avatar stack after the offlineTimeout has elapsed
space.members.subscribe('remove', (member) => {
renderAvatars('removeMember', member);
});
CopyCopied!Avatar stack foundations
The Spaces SDK is built upon existing Ably functionality available in Ably’s Core SDKs. Understanding which core features are used to provide the abstractions in the Spaces SDK enables you to manage space state and build additional functionality into your application.
Avatar stacks build upon the functionality of the Pub/Sub Channels presence feature. Members are entered into the presence set when they enter the space.