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Join channels

Requires App Context

Enable App Context on your keyset in the Admin Portal to manage memberships.

Use join() to connect a user to a channel and create a membership. The user can receive messages and is recorded as a channel member.

Interactive demo​

Check what a sample implementation could look like in a React app showcasing user-channel membership.

Want to implement something similar?

Read how to do that or go straight to the demo's source code.

Test it out​

Choose whether you want to join or leave a given channel and wait until you get notified when that happens.

Method signature​

icon

Under the hood


join() accepts a callback function and a set of parameters as arguments. The Chat SDK invokes this callback whenever the current user receives a new message on a channel they have just joined. It subscribes the user to a channel and adds a message event listener underneath. The method also sets user and channel membership by creating a new Membership object that holds the user-channel relationship.

This method takes the following parameters:

1channel.join(
2    callback: (message: Message) => void, 
3    {
4        custom?: ObjectCustom
5    }
6): Promise<{
7    membership: Membership;
8    disconnect: () => void;
9}>

Input​

* required
ParameterDescription
callback *
Type: n/a
Default:
n/a
Callback function passed as a parameter. It defines the custom behavior to be executed when detecting a new Message object on the joined channel.
 → message *
Type: Message
Default:
n/a
Any Message object received on the joined channel.
 → custom
Type: ObjectCustom
Default:
n/a
Any custom properties or metadata associated with the channel-user membership in the form of a JSON. Values must be scalar only; arrays or objects are not supported. App Context filtering language doesn’t support filtering by custom properties.

Output​

TypeDescription
Promise<Membership>
Returned object containing all membership data.
ParameterDescription
Promise<>
Type: object
Returned object containing two fields: membership and disconnect.
 → membership
Type: Membership
Returned object containing info on the newly created user-channel membership.
 → disconnect
Type: () => void
Function that lets you stop listening to new channel messages or message updates while remaining a channel membership. This might be useful when you want to stop receiving notifications about new messages or limit incoming messages or updates to reduce network traffic.

Sample code​

Join the support channel and mark this membership as premium to add information about your support plan.

1// reference the "channel" object
2const channel = await chat.getChannel("support")
3

4// join the channel and add metadata to the newly created membership
5await channel.join(
6    (data) => {
7       console.log(
8            "This is my first message on this channel! Nice to meet you all!", data
9        )
10    },
11    {
12        custom: {support_plan: "premium"}
13    }
14)
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