> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-22654f5b-docs-rn-guide-message-privately.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Join A Group

> Join A Group — CometChat documentation.

## Join a Group

In order to start participating in group conversations, you will have to join a group. You can do so using the `joinGroup()` method.

<Tabs>
  <Tab title="Join Group">
    ```javascript theme={null}
    var GUID = "GUID";
    var password = "";
    var groupType = CometChat.GROUP_TYPE.PUBLIC;

    CometChat.joinGroup(GUID, groupType, password).then(
    group => {
      console.log("Group joined successfully:", group);
    }, error => {
      console.log("Group joining failed with exception:", error);
    }
    );
    ```
  </Tab>

  <Tab title="TypeScript">
    ```typescript theme={null}
    var GUID: string = "GUID";

    CometChat.joinGroup(GUID, CometChat.GroupType.Public).then(
      (group: CometChat.Group) => {
          console.log("Group joined successfully:", group);
      }, (error: CometChat.CometChatException) => {
          console.log("Group joining failed with exception:", error);
      }
    );
    ```
  </Tab>
</Tabs>

The `joinGroup()` method takes the below parameters

| Parameter   | Description                                                                                                                                                      |
| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `GUID`      | The GUID of the group you would like to join.                                                                                                                    |
| `groupType` | Type of the group. CometChat provides 3 types of groups viz. 1. CometChat.GROUP\_TYPE.PUBLIC 2. CometChat.GROUP\_TYPE.PASSWORD 3. CometChats.GROUP\_TYPE.PRIVATE |
| `password`  | Password is mandatory in case of a password protected group.                                                                                                     |

Once you have joined a group successfully, you can send and receive messages in that group.

CometChat keeps a track of the groups joined and you do not need to join the group every time you want to communicate in the group.

You can identify if a group is joined using the `hasJoined` parameter in the `Group` object.

## Real-time Group Member Joined Events

*In other words, as a member of a group, how do I know if someone joins the group when my app is running?*

If a user joins any group, the members of the group receive a real-time event in the `onGroupMemberJoined()` method of the `GroupListener` class.

<Tabs>
  <Tab title="Group Listener">
    ```javascript theme={null}
    CometChat.addGroupListener(
      "UNIQUE_LISTNER_ID",
      new CometChat.GroupListener({
          onGroupMemberJoined: (message, joinedUser, joinedGroup) => {
              console.log("User joined", { message, joinedUser, joinedGroup });
          }
      })
    );
    ```
  </Tab>

  <Tab title="TypeScript">
    ```typescript theme={null}
    CometChat.addGroupListener(
      "UNIQUE_LISTNER_ID",
      new CometChat.GroupListener({
          onGroupMemberJoined: (message: CometChat.Action, joinedUser: CometChat.User, joinedGroup: CometChat.Group) => {
              console.log("User joined", { message, joinedUser, joinedGroup });
          }
      })
    );
    ```
  </Tab>
</Tabs>

## Missed Group Member Joined Events

*In other words, as a member of a group, how do I know if someone joins the group when my app is not running?*

When you retrieve the list of previous messages if a member has joined any group that the logged-in user is a member of, the list of messages will contain an `Action` message. An `Action` message is a sub-class of `BaseMessage` class.

For the group member joined event, in the `Action` object received, the following fields can help you get the relevant information-

1. `action` - `joined`
2. `actionBy` - User object containing the details of the user who joined the group
3. `actionFor`- Group object containing the details of the group the user has joined