How to add users to Liveblocks Comments

After following the get started guide for Comments, you’ll notice that each user is currently “Anonymous”, and that there’s no way to mention or tag other users. To enable these features, we need to tell Comments where to find your users’ information.

What we’re learning

In this guide we’ll be modifying LiveblocksProvider, learning how to:

• Add names and avatars to threads and comments with resolveUsers.
• Create user mention suggestions in the composer using resolveMentionSuggestions.

Authenticate your application

The first step is to find an authentication guide for your framework and authenticate your app, as this is necessary for Comments.

Make sure to follow the metadata step in the guide, and attach the name of your user, along with the URL of their avatar, as these properties will both be used in the default components. Here’s an example using access token authentication, with an email address as a user’s ID.

const session = liveblocks.prepareSession("marc@example.com", {  userInfo: {    name: "Marc",    avatar: "https://example.com/marc.png",
    // Your custom metadata    // ...  },});

If you’re using ID token authentication, it’ll look a little different.

Don’t forget to modify your UserMeta type in liveblocks.config.ts to match the metadata format, adding type hints to your editor.

declare global {  interface Liveblocks {    UserMeta: {      id: string;
      info: {        name: string;        avatar: string;
        // Your custom metadata        // ...      };    };  }}

Resolving users

To show each user’s name and avatar in threads and comments, we need to use resolveUsers.

1. Add the function to your LiveblocksProvider

   The resolveUsers function is passed as an option to LiveblocksProvider—let’s add it. This function provides you with userIds, an array of user IDs that have interacted with Comments. These userIds match the IDs set when authenticating users in your app.

   <LiveblocksProvider  resolveUsers={async ({ userIds }) => {    // ["marc@example.com", ...]    console.log(userIds);
       // Return a list of users    // ...  }}
     // .../>;

2. Return your users

   resolveUsers requires you to return a list of users in the UserMeta["info"] format we set earlier. Remember that name and avatar are required for the default components, but you can also use any other metadata in your app.

   <LiveblocksProvider  resolveUsers={async ({ userIds }) => {    // ["marc@example.com", ...]    console.log(userIds);
       // Return a list of users    return [      {        name: "Marc",        avatar: "https://example.com/marc.png",
           // Your custom metadata        // ...      },      // ...    ];  }}
     // .../>;

   We’re only returning one user here, but make sure to return an array containing each user, in the same order you received the IDs.

3. Real-world example

   In your real application you’ll probably be getting users from your API endpoint and database via fetch. This is how we’d recommend building out this function.

   <LiveblocksProvider  resolveUsers={async ({ userIds }) => {    // Get users from your back end    const users = await __fetchUsers__(userIds);
       // Return a list of users    return users;  }}
     // .../>;

4. Users are now visible

   After adding this, you should now be able to see your users in threads!

   

Resolving mention suggestions

We can see the users that have commented, but we don’t have a way to search for users to mention, for example after typing the @ character. We can create a simple search that resolves this data with resolveMentionSuggestions.

1. Add the function to your config file

   resolveMentionSuggestions is placed alongside resolveUsers, and provides you with text, which is the string that the user is searching for. You can use this string to return a list of matching user IDs.

   <LiveblocksProvider  resolveUsers={async ({ userIds }) => {    // ...  }}  resolveMentionSuggestions={async ({ text, roomId }) => {    // The text the user is searching for, e.g. "mar"    console.log(text);
       // Return a list of user IDs that match the query    return ["marc@example.com", "marissa@example.com"];  }}
     // .../>;

2. Real-world example

   In a real application, you’ll most likely be getting a list of each user, before filtering the list by the user’s names or IDs. If text is an empty string, then you need to return a list of every user, instead of a filtered list.

   <LiveblocksProvider  resolveUsers={async ({ userIds }) => {    // ...  }}  resolveMentionSuggestions={async ({ text, roomId }) => {    // Fetch all users from your back end    let users = await __fetchAllUsers__();
       // If there's a query, filter for the relevant users    if (text) {      // Filter any way you'd like, e.g. checking if the name matches      users = users.filter((user) => user.name.includes(text));    }
       // Return the filtered `userIds`    return users.map((user) => user.id);  }}
     // .../>;

3. Mention suggestions now appear

   Now we’ve found and returned the correct users, Comments can display a list of mention suggestions!

   

Next steps

You’re now ready to start building your Comments application! Here’s where you can learn more:

• API reference
• Component reference
• Examples