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Use custom user type in Passport.js with Typescript

Used versions​

  • Node.js: 19.6.0
  • Typescript: 5.1.3
  • Express: 4.18.2
  • Passport: 0.6.0

Problem​

The default user type used for serializing the user (passport.serializeUser(user, done)) is Express.User. This type is defined in the @types/passport/index.d.ts file as:

declare global {
  namespace Express {
    interface User {}
  }
}

This is a problem if you want to use a custom user type (e.g.: a User model from a database).

Solution​

First, import the the customer type you want to use in the @types/passport/index.d.ts file:

import { User } from "../../src/models/user.model";

Then, delete or comment the User interface:

declare global {
  namespace Express {
    // interface User {}
  }
}

Finally, add the User type to the serializeUser function:

passport.serializeUser((user: User, done) => {
  done(null, user.id);
});