The saveToken() function must be implemented for all grant types in the model used by OAuth2Server. This function stores the access token as an object to a database when an access token is obtained.

The saveToken() function is implemented with three arguments: token, client, and user. We set the token.client to an object where the id attribute is equal to the passed client’s clientId. The client is formatted like below:

const saveToken = (token, client, user) => {
  token.client = {
    id: client.clientId
  }
}

The token.user is set to an object with the username attribute. We set the username to the username of the passed user object. The username is formatted like below:

token.user = {
  username: user.username
}

With the token formatted, we can save the token to our database by pushing the token to our db.tokens array and returning the token.

db.tokens.push(token);
return token

Our final saveToken() function looks like below:

const saveToken = (token, client, user) => {
  token.client = {
    id: client.clientId
  }
  token.user = {
    username: user.username
  }
  db.tokens.push(token);
  return token;
}

We’ll also export the saveToken() function from models.js using the modules.export.