drop cap ab test: add migration to enroll all web users

migrations/archive/2020/20201103_drop_cap_ab_tweaks.js

@@ -0,0 +1,62 @@
+/*
+ * All web users should be enrolled in the Drop Cap AB Test
+ */
+/* eslint-disable no-console */
+
+const MIGRATION_NAME = '20201103_drop_cap_ab_tweaks';
+
+import { model as User } from '../../../website/server/models/user';
+
+const progressCount = 1000;
+let count = 0;
+
+async function updateUser (user) {
+  count++;
+
+  const set = {};
+
+  set.migration = MIGRATION_NAME;
+
+  const testGroup = Math.random();
+  // Enroll 100% of users, splitting them 50/50
+  const value = testGroup <= 0.50 ? 'drop-cap-notif-enabled' : 'drop-cap-notif-disabled';
+  set['_ABtests.dropCapNotif'] = value;
+
+  if (count % progressCount === 0) console.warn(`${count} ${user._id}`);
+  return await User.update({_id: user._id}, {$set: set}).exec();
+}
+
+module.exports = async function processUsers () {
+  let query = {
+    migration: {$ne: MIGRATION_NAME},
+    'auth.timestamps.loggedin': {$gt: new Date('2020-10-10')},
+    '_ABtests.dropCapNotif': 'drop-cap-notif-not-enrolled',
+  };
+
+  const fields = {
+    _id: 1,
+    _ABtests: 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
+  }
+};