habitica/migrations/users/bulk-email.js

/* eslint-disable no-console */
import { sendTxn } from '../../website/server/libs/email';
import { model as User } from '../../website/server/models/user';
import moment from 'moment';
import nconf from 'nconf';
const BASE_URL = nconf.get('BASE_URL');
const EMAIL_SLUG = 'mandrill-email-slug'; // Set email template to send
const MIGRATION_NAME = 'bulk-email';

const progressCount = 1000;
let count = 0;

async function updateUser (user) {
  count++;

  if (count % progressCount === 0) console.warn(`${count} ${user._id}`);

  sendTxn(
    user,
    EMAIL_SLUG,
    [{name: 'BASE_URL', content: BASE_URL}] // Add variables from template
  );

  return await User.update({_id: user._id}, {$set: {migration: MIGRATION_NAME}}).exec();
}

module.exports = async function processUsers () {
  let query = {
    migration: {$ne: MIGRATION_NAME},
    'auth.timestamps.loggedin': {$gt: moment().subtract(2, 'weeks').toDate()}, // customize or remove to target different populations
  };

  const fields = {
    _id: 1,
    auth: 1,
    preferences: 1,
    profile: 1,
  };

  while (true) { // eslint-disable-line no-constant-condition
    const users = await User // eslint-disable-line no-await-in-loop
      .find(query)
      .limit(250)
      .sort({_id: 1})
      .select(fields)
      .lean()
      .exec();

    if (users.length === 0) {
      console.warn('All appropriate users found and modified.');
      console.warn(`\n${count} users processed\n`);
      break;
    } else {
      query._id = {
        $gt: users[users.length - 1],
      };
    }

    await Promise.all(users.map(updateUser)); // eslint-disable-line no-await-in-loop
  }
};