Channel Read State

This guide intends to provide an overview how channel read state is handled by default in the SDK and how to customize this behavior to our liking.

The model

The React Native SDK manages the channel’s read state specifically for UI components within the Channel component using a separate state variable called channelUnreadState. This state is primarily used to display the unread message count in components like InlineUnreadIndicator and UnreadMessagesNotification, as well as custom components requiring similar functionality. A unique aspect of channelUnreadState is that when a channel is opened and marked as read, it does not immediately reflect this update. This behavior ensures the user can see the number of unread messages remaining from their previous session.

Channel read state reflecting the current back-end state can be accessed via channel.state.read mapping.

Channel UI unread state

The state is maintained by Channel component and shared with its children via ChannelContext as channelUnreadState. The state format is as follows:

Channel read state for all users

The read state is extracted from the channel query response, specifically from each ChannelResponse object’s read attribute. This is internally transformed from an array of users’ read statuses into and object indexed by user id. The read state is updated upon receiving WS events like message.read, notification.mark_unread, message.new. Each value of the read state object has then the following structure:

Access the read state

In the SDK, the read and channelUnreadState can be accessed via useChannelContext consumer:

import { useChannelContext, useChatContext } from "stream-chat-react-native";

const Component = (props) => {
  const { client } = useChatContext();
  const { read, channel, channelUnreadState } = useChannelContext();

  // channel read state for some user
  const channelReadStateForAUser = read[props.user.id];

  // channel read state for own user
  const channelReadStateForMyUser = client.user && read[client.user.id];

  // easier way to access own user's unread count for a given channel
  const unreadCount = channel.unreadCount();

  //... code
};

Mark a channel read

Channel can be marked read using the markRead() function provided via ChannelContext:

import { Button } from "react-native";
import { useChannelContext } from "stream-chat-react-native";

const MarkReadButton = (props) => {
  const { markRead } = useChannelContext();

  return (
    <Button {...props} onClick={() => markRead()}>
      Mark read
    </Button>
  );
};

The function accepts a single options parameter of the following format:

Default components involved in handling read state

The default components included in marking a channel read:

The message actions in the menu already has a action added to mark a message as unread and that will be reflected on the Channel state. You can go through our Customizing message actions guide.

The default components reflecting channel unread count:

Default channel read state handling

The channel is marked read in the following scenarios:

1. User enters a channel with unread messages if Channel prop markReadOnMount is enabled (default behavior).
2. User scrolls up and back down to the latest message.
3. User clicks the button on the default UnreadMessagesNotification component to jump to the first unread message.
4. The ScrollToBottomButton would appears that can take you to the latest message on click.

The channel is marked unread in the following scenarios:

1. User with read-events permission is shown Mark as unread option in the message actions list.

The component InlineUnreadIndicator is shown immediately below the last read message. It can be followed by own message or a message posted by another user.

Channel read state handling customization

Customization through component props

There is a possibility to configure when a channel is marked read by tweaking these default components’ props:

Customization through custom components

We can override the following components via passing a custom UI component to Channel component:

Custom InlineUnreadIndicator component

Will be rendered before the first unread message.

import { Channel } from "stream-chat-react-native";

const InlineUnreadIndicator = () => {
  //... custom implementation
};

const Component = ({ children }) => (
  <Channel InlineUnreadIndicator={InlineUnreadIndicator}>{children}</Channel>
);

Custom UnreadMessagesNotification component

Will be rendered only when UnreadMessagesSeparator is not visible in message list. The default implementation positions the notification as a floating element above the messages in a message list. It shows the number of unread messages since the user has scrolled away from the latest message (bottom of the message list).

import {
  Channel,
  UnreadMessagesNotificationProps,
} from "stream-chat-react-native";

const UnreadMessagesNotification = (props: UnreadMessagesNotificationProps) => {
  //... custom implementation
};

const Component = ({ children }) => (
  <Channel UnreadMessagesNotification={UnreadMessagesNotification}>
    {children}
  </Channel>
);

The component can be configured through the following props:

Custom ScrollToBottomButton component

The SDK exports ScrollToBottomButton that shows the unread count since the point the user has scrolled away from the newest messages in the list.

We can implement our own message scroll to bottom button component.

import { Channel, ScrollToBottomButtonProps } from "stream-chat-react-native";

const ScrollToBottomButton = (props: ScrollToBottomButtonProps) => {
  //... custom implementation
};

const Component = ({ children }) => (
  <Channel ScrollToBottomButton={ScrollToBottomButton}>{children}</Channel>
);

Jumping to the first unread message

Initial scroll to first unread messages on mount

The behaviour can be enabled by enabling the prop initialScrollToFirstUnreadMessage in the Channel component.

Default SDK component to jump to the first unread message

The SDK provides a component UnreadMessagesNotification, that when clicked on the part Unread messages, the message list scrolls to the first unread message. If the first unread message is not loaded in the local channel state, the message is retrieved from the API.

API to jump to the first unread message

Use loadChannelAtFirstUnreadMessage() function to implement custom UI to jump to the first unread message. The function taks parameters like limit, channelUnreadState, setChannelUnreadState, setTargetedMessage. The channelUnreadState, setChannelUnreadState, setTargetedMessage can be used from useChannelContext.

Showing total unread counts in the app

To show the total un-read counts in your app, when you connect to a client, you can do the following:

1. You get the total un-read count in the response of the client.connectUser() call and you can use the response to store the total count.

const [unreadCount, setUnreadCount] = useState<number>();

const client = StreamChat.getInstance<StreamChatGenerics>("Your API Key", {
  timeout: 6000,
});

const user = {
  id: "Your User ID",
};
const connectedUser = await client.connectUser(user, "Your User Token");
const initialUnreadCount = connectedUser?.me?.total_unread_count; // Use it to show the total unread count on the initial load.

2. To listen to the total un-read count changes as different actions/events are performed/received in the SDK, you can rely on the client event listener:

useEffect(() => {
  const listener = client?.on((e) => {
    if (e.total_unread_count !== undefined) {
      setUnreadCount(e.total_unread_count);
    } else {
      const countUnread = Object.values(chatClient.activeChannels).reduce(
        (count, channel) => count + channel.countUnread(),
        0,
      );
      setUnreadCount(countUnread);
    }
  });

  return () => {
    if (listener) {
      listener.unsubscribe();
    }
  };
}, [chatClient]);