habitica/migrations/command-line/find_unique_user.js

// mongo habitrpg ./node_modules/lodash/index.js ./migrations/find_unique_user.js

/**
 * There are some rare instances of lost user accounts, due to a corrupt user auth variable (see https://github.com/lefnire/habitrpg/wiki/User-ID)
 * Past in the text of a unique habit here to find the user, then you can restore their UUID
 */

db.users.find().forEach(user => {
  user.tasks = user.habits.concat(user.dailys).concat(user.todos).concat(user.rewards);
  const found = _.some(user.tasks, { text: '' });
  if (found) printjson({ id: user._id, auth: user.auth });
});