Mark messages as read

In a group channel, the read status of messages is crucial for understanding which messages have been read by which members. This document explains how to mark messages as read in a group channel.

To keep the most up-to-date and accurate read status of messages for all group channel members, the markAsRead() method should be called in the following cases:

• When a channel member enters the channel and reads messages.
• When a channel member switches the chat view from the background to the foreground.

When a member sends a message in a group channel, the Sendbird server updates the member's read receipt to the time when the message was sent. The read receipts of other channel members are updated when the markAsRead() method is called.

If a member enters a channel and markAsReadAll() is called, the Sendbird server updates the following:

• The unread message count of the individual channel.
• The total unread message count of all the group channels joined by the member.

The server then triggers the onUserMarkedRead() method in the channel event handler to notify the change of read status to all other members' devices.

// const sb = SendbirdChat.init(...); // For Sendbird Chat SDK initialization details, refer to:
// https://sendbird.com/docs/chat/sdk/v4/javascript/getting-started/send-first-message#2-get-started-3-step-2-initialize-sendbird-chat-sdk

await groupChannel.markAsRead();
// ...

const channelHandler = new GroupChannelHandler({
    onUserMarkedRead: (channel, userIds) => {
        // ...
    }
});
sb.groupChannel.addGroupChannelHandler(UNIQUE_HANDLER_ID, channelHandler);

If a new member joins the channel, the method works differently based on the value of the display_past_message property of your Sendbird application. The display_past_message property determines whether to display past messages to newly joined members when they enter the channel.

If the property is set to true, the new member’s read receipt is updated to the sent time of the last message in the channel. If set to false, the property's value is 0.

Note: This property is also linked to the Chat history option, which can be managed on Sendbird Dashboard under Settings > Chat > Channels > Group channels.