Is there any way within FusionAuth to enforce the uniqueness of a username within an application?

joshua

joshua

The username on the user (user.username) is unique and can be used to login. The username on the registration registration.username is not unique and cannot be used to login, it is intended to be used for display in an application.

kasir-barati

Hey @joshua,

Thanks for this Q&A, I have a question, what does this uniqueUsername mean and how it differs from username? E.g. code written in TS:

await fusionAuthClient.updateUser(id, {
  user: {
    uniqueUsername: username,
  },
});

// vs
await fusionAuthClient.updateUser(id, {
  user: {
    username: username,
  },
});

How I register a user:

await fusionAuthClient.register('', {
  sendSetPasswordEmail: true,
  skipVerification: false,
  registration: {
    applicationId,
  },
  user: {
    email,
    lastName,
    firstName,
    memberships,
    fullName: `${firstName} ${lastName}`,
    username,
  },
});

Side note

I need username to be unique and I am utilizing @fusionauth/react-sdk's useFusionAuth hook. So basically IDK whether user.preferred_username is gonna be filled when I use uniqueUsername both in registration and updateUser or not.

And if the answer is negative* then should I manually write code to enforce uniqueness of username in my NestJS app?

*meaning if I use uniqueUsername in my frontend app preferred_username would be undefined