Migration script for Nova Users to run server-side: from user.telescope.settingX to user.__settingX (without removing user.telescope.settingX for backward compatibility)

nova-users-apollo-migration.js

// Explanation: 
// This is a migration script for your users to be compatible with the Apollo version of Nova
// We do not support anymore users properties on the `telescope` namespace. They will be duplicated onto __setting:
// Example: `user.telescope.karma` becomes `user.__karma`
// Note: we do not remove the `user.telescope` object, you'll still be able to go back to your previous full Meteor build if you feel that Apollo doesn't fit your needs

// How to use:
// Copy/paste the script below at the end of the nova:users /packages/nova-users/lib/server.js (package's server entry-point)

Meteor.startup(function runMigrationToApollo() {
  
  // find users with telescope fields (full-Meteor Nova) and an arbitrary Apollo user setting 
  const usersCursor = Users.find({telescope: {$exists: true}, __karma: {$exists: false}});
  
  const usersCount = usersCursor.count();
  const users = usersCursor.fetch();

  console.log('// --------------------------------------------------------');
  console.log('// Nova Users migration to Apollo data');

  // zero user to migrate \o/
  if (!usersCount) {
    console.log('// Status: All good! 👍 We didn\'t find any user to migrate! ');
    console.log('// ====> You should remove this script from your application! 🔭');
    console.log('// --------------------------------------------------------');
    
    return;
  }

  console.log(`// Status: Starting the migration, ${usersCount} users to migrate... (it may take some time)`);
  
  // duplicate telescope namespace to the root of the user object
  const apolloUsers = users.map(user => {
    // telescopeNamespace.bio = "Hey, I'm a Telescope Nova user!"
    // telescopeNamespace.email = "xxx@xxx.com"
    // telescopeNamespace.displayName = "John Doe"
    // telescopeNamespace.x = y
    const telescopeNamespace = user.telescope;

    // "bio" => {__bio: "Hey, I'm a Telescope Nova user!"}
    // "email" => {__email: "xxx@xxx.com"}
    // "displayName" => {__displayName: "John Doe"}
    // "x" => {__x: y}
    const arrayOfSettings = Object.keys(telescopeNamespace).map(key => {
      return {[`__${key}`]: telescopeNamespace[key]};
    });
    
    // {
    //   __bio: "Hey, ...",
    //   __email: "xxx@xxx.com",
    //   __displayName: "John Doe",
    //   __x: "y"
    // }
    const newSettings = arrayOfSettings.reduce((result, item) => {
      return {
        ...result,
        ...item
      };
    }, {});
    
    // {
    //   _id: "yvZfYTWC8HZggSEa5",
    //   __bio "Hey, ...",
    //   __email: "xxx@xxx.com",
    //   __displayName: "John Doe",
    //   __x: "y"
    // }
    return {
      _id: user._id,
      ...newSettings
    };
  });
  
  // migrate the users with the new settings
  const migratedUsers = apolloUsers.map(apolloUserSettings => {
    const userId = apolloUserSettings._id;
    delete apolloUserSettings._id; // maybe not needed ? this is to avoid overwritting the _id, even if it's the same

    return Users.update({_id: userId}, {$set: apolloUserSettings});
  });
  
  // maybe do something on migratedUsers to check if there any false value (update failure) and log it? could this happen? Mongo connection lost?

  console.log('// Status: Migration of Users to Apollo completed! 👍')
  console.log('// ====> You should remove this script from your application! 🔭');
  console.log('// --------------------------------------------------------');

});

Feedbacks and contributions on this snippet are more than welcomed! 👍

What about also logging the migration to the Migrations collection? The previous migrations script would insert the following properties:

name
startedAt
completed (true/false)
itemsAffected
finishedAt

Another thing that might be useful is set a special __hasMigrated flag on a user profile once it's been migrated. This way if the user has to interrupt and re-run the migration for some reason they don't need to re-migrate everything.

For reference: https://github.com/TelescopeJS/Telescope/blob/apollo/packages/_nova-migrations/lib/server/migrations.js