From aa9d6c8dc95f3032e920890916e59c611ede8f22 Mon Sep 17 00:00:00 2001
From: Jakob Ackermann <jakob.ackermann@overleaf.com>
Date: Tue, 7 Jul 2020 12:06:02 +0200
Subject: [PATCH] [misc] reland decaff cleanup (#166)

* [misc] decaff cleanup: RoomManager

* [misc] decaff cleanup: RedisClientManager

* [misc] decaff cleanup: SafeJsonParse

* [misc] decaff cleanup: WebApiManager

* [misc] decaff cleanup: WebsocketController

* [misc] decaff cleanup: WebsocketLoadBalancer

* [misc] decaff cleanup: SessionSockets

* [misc] decaff cleanup: HttpController

* [misc] decaff cleanup: HttpApiController

* [misc] decaff cleanup: HealthCheckManager

* [misc] decaff cleanup: EventLogger

* [misc] decaff cleanup: Errors

o-error will eliminate most of it -- when we migrate over.

* [misc] decaff cleanup: DrainManager

* [misc] decaff cleanup: DocumentUpdaterManager

* [misc] decaff cleanup: DocumentUpdaterController: no-unused-vars

* [misc] decaff cleanup: DocumentUpdaterController: Array.from

* [misc] decaff cleanup: DocumentUpdaterController: implicit return

* [misc] decaff cleanup: DocumentUpdaterController: IIFE

* [misc] decaff cleanup: DocumentUpdaterController: null checks

* [misc] decaff cleanup: DocumentUpdaterController: simpler loops

* [misc] decaff cleanup: DocumentUpdaterController: move module name def

* [misc] decaff cleanup: ConnectedUsersManager: handle-callback-err

* [misc] decaff cleanup: ConnectedUsersManager: implicit returns

* [misc] decaff cleanup: ConnectedUsersManager: null checks

* [misc] decaff cleanup: ChannelManager: no-unused-vars

* [misc] decaff cleanup: ChannelManager: implicit returns

* [misc] decaff cleanup: ChannelManager: other cleanup

- var -> const
- drop variable assignment before return

* [misc] decaff cleanup: AuthorizationManager: handle-callback-err

Note: This requires a change in WebsocketController to provide a dummy
 callback.

* [misc] decaff cleanup: AuthorizationManager: Array.from

* [misc] decaff cleanup: AuthorizationManager: implicit returns

* [misc] decaff cleanup: AuthorizationManager: null checks

* [misc] decaff cleanup: Router: handle-callback-err

* [misc] decaff cleanup: Router: standard/no-callback-literal

* [misc] decaff cleanup: Router: Array.from

* [misc] decaff cleanup: Router: implicit returns

* [misc] decaff cleanup: Router: refactor __guard__ wrapper

* [misc] decaff cleanup: Router: null checks

And a minor bug fix: user.id -> user._id

* [misc] decaff cleanup: Router: move variable declarations to assignments

* [misc] decaff cleanup: app: implicit returns

* [misc] decaff cleanup: app: __guard__

* [misc] decaff cleanup: app: null checks

* [misc] decaff cleanup: app: function definitions

* [misc] decaff cleanup: app: drop unused next argument

* [misc] decaff cleanup: app: var -> const
---
 services/real-time/app.js                     |  86 +++----
 .../real-time/app/js/AuthorizationManager.js  |  76 ++----
 services/real-time/app/js/ChannelManager.js   |  37 ++-
 .../real-time/app/js/ConnectedUsersManager.js | 112 ++++-----
 .../app/js/DocumentUpdaterController.js       | 106 +++------
 .../app/js/DocumentUpdaterManager.js          |  60 ++---
 services/real-time/app/js/DrainManager.js     |  34 +--
 services/real-time/app/js/Errors.js           |  22 +-
 services/real-time/app/js/EventLogger.js      |  34 +--
 .../real-time/app/js/HealthCheckManager.js    |  38 +--
 .../real-time/app/js/HttpApiController.js     |  26 +--
 services/real-time/app/js/HttpController.js   |  58 ++---
 .../real-time/app/js/RedisClientManager.js    |  45 +---
 services/real-time/app/js/RoomManager.js      | 115 ++++------
 services/real-time/app/js/Router.js           | 216 +++++++----------
 services/real-time/app/js/SafeJsonParse.js    |  18 +-
 services/real-time/app/js/SessionSockets.js   |  16 +-
 services/real-time/app/js/WebApiManager.js    |  35 +--
 .../real-time/app/js/WebsocketController.js   | 217 +++++++-----------
 .../real-time/app/js/WebsocketLoadBalancer.js | 115 +++-------
 20 files changed, 483 insertions(+), 983 deletions(-)

diff --git a/services/real-time/app.js b/services/real-time/app.js
index b34b33df61..1580f18027 100644
--- a/services/real-time/app.js
+++ b/services/real-time/app.js
@@ -1,10 +1,3 @@
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * DS103: Rewrite code to no longer use __guard__
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
 const Metrics = require('metrics-sharelatex')
 const Settings = require('settings-sharelatex')
 Metrics.initialize(Settings.appName || 'real-time')
@@ -17,7 +10,7 @@ Metrics.event_loop.monitor(logger)
 const express = require('express')
 const session = require('express-session')
 const redis = require('redis-sharelatex')
-if ((Settings.sentry != null ? Settings.sentry.dsn : undefined) != null) {
+if (Settings.sentry && Settings.sentry.dsn) {
   logger.initializeErrorReporting(Settings.sentry.dsn)
 }
 
@@ -70,44 +63,43 @@ io.configure(function () {
     'xhr-polling',
     'jsonp-polling'
   ])
-  return io.set('log level', 1)
+  io.set('log level', 1)
 })
 
-app.get('/', (req, res, next) => res.send('real-time-sharelatex is alive'))
+app.get('/', (req, res) => res.send('real-time-sharelatex is alive'))
 
-app.get('/status', function (req, res, next) {
+app.get('/status', function (req, res) {
   if (Settings.shutDownInProgress) {
-    return res.send(503) // Service unavailable
+    res.send(503) // Service unavailable
   } else {
-    return res.send('real-time-sharelatex is alive')
+    res.send('real-time-sharelatex is alive')
   }
 })
 
-app.get('/debug/events', function (req, res, next) {
-  Settings.debugEvents =
-    parseInt(req.query != null ? req.query.count : undefined, 10) || 20
+app.get('/debug/events', function (req, res) {
+  Settings.debugEvents = parseInt(req.query.count, 10) || 20
   logger.log({ count: Settings.debugEvents }, 'starting debug mode')
-  return res.send(`debug mode will log next ${Settings.debugEvents} events`)
+  res.send(`debug mode will log next ${Settings.debugEvents} events`)
 })
 
 const rclient = require('redis-sharelatex').createClient(
   Settings.redis.realtime
 )
 
-const healthCheck = (req, res, next) =>
+function healthCheck(req, res) {
   rclient.healthCheck(function (error) {
-    if (error != null) {
+    if (error) {
       logger.err({ err: error }, 'failed redis health check')
-      return res.sendStatus(500)
+      res.sendStatus(500)
     } else if (HealthCheckManager.isFailing()) {
       const status = HealthCheckManager.status()
       logger.err({ pubSubErrors: status }, 'failed pubsub health check')
-      return res.sendStatus(500)
+      res.sendStatus(500)
     } else {
-      return res.sendStatus(200)
+      res.sendStatus(200)
     }
   })
-
+}
 app.get('/health_check', healthCheck)
 
 app.get('/health_check/redis', healthCheck)
@@ -125,30 +117,30 @@ const { port } = Settings.internal.realTime
 const { host } = Settings.internal.realTime
 
 server.listen(port, host, function (error) {
-  if (error != null) {
+  if (error) {
     throw error
   }
-  return logger.info(`realtime starting up, listening on ${host}:${port}`)
+  logger.info(`realtime starting up, listening on ${host}:${port}`)
 })
 
 // Stop huge stack traces in logs from all the socket.io parsing steps.
 Error.stackTraceLimit = 10
 
-var shutdownCleanly = function (signal) {
-  const connectedClients = __guard__(io.sockets.clients(), (x) => x.length)
+function shutdownCleanly(signal) {
+  const connectedClients = io.sockets.clients().length
   if (connectedClients === 0) {
     logger.warn('no clients connected, exiting')
-    return process.exit()
+    process.exit()
   } else {
     logger.warn(
       { connectedClients },
       'clients still connected, not shutting down yet'
     )
-    return setTimeout(() => shutdownCleanly(signal), 30 * 1000)
+    setTimeout(() => shutdownCleanly(signal), 30 * 1000)
   }
 }
 
-const drainAndShutdown = function (signal) {
+function drainAndShutdown(signal) {
   if (Settings.shutDownInProgress) {
     logger.warn({ signal }, 'shutdown already in progress, ignoring signal')
   } else {
@@ -160,20 +152,20 @@ const drainAndShutdown = function (signal) {
         `received interrupt, delay drain by ${statusCheckInterval}ms`
       )
     }
-    return setTimeout(function () {
+    setTimeout(function () {
       logger.warn(
         { signal },
         `received interrupt, starting drain over ${shutdownDrainTimeWindow} mins`
       )
       DrainManager.startDrainTimeWindow(io, shutdownDrainTimeWindow)
-      return shutdownCleanly(signal)
+      shutdownCleanly(signal)
     }, statusCheckInterval)
   }
 }
 
 Settings.shutDownInProgress = false
-if (Settings.shutdownDrainTimeWindow != null) {
-  var shutdownDrainTimeWindow = parseInt(Settings.shutdownDrainTimeWindow, 10)
+const shutdownDrainTimeWindow = parseInt(Settings.shutdownDrainTimeWindow, 10)
+if (Settings.shutdownDrainTimeWindow) {
   logger.log({ shutdownDrainTimeWindow }, 'shutdownDrainTimeWindow enabled')
   for (const signal of [
     'SIGINT',
@@ -188,9 +180,7 @@ if (Settings.shutdownDrainTimeWindow != null) {
   } // signal is passed as argument to event handler
 
   // global exception handler
-  if (
-    Settings.errors != null ? Settings.errors.catchUncaughtErrors : undefined
-  ) {
+  if (Settings.errors && Settings.errors.catchUncaughtErrors) {
     process.removeAllListeners('uncaughtException')
     process.on('uncaughtException', function (error) {
       if (['EPIPE', 'ECONNRESET'].includes(error.code)) {
@@ -201,12 +191,8 @@ if (Settings.shutdownDrainTimeWindow != null) {
         )
       }
       logger.error({ err: error }, 'uncaught exception')
-      if (
-        Settings.errors != null
-          ? Settings.errors.shutdownOnUncaughtError
-          : undefined
-      ) {
-        return drainAndShutdown('SIGABRT')
+      if (Settings.errors && Settings.errors.shutdownOnUncaughtError) {
+        drainAndShutdown('SIGABRT')
       }
     })
   }
@@ -227,26 +213,20 @@ if (Settings.continualPubsubTraffic) {
       date: new Date().toString()
     })
     Metrics.summary(`redis.publish.${channel}`, json.length)
-    return pubsubClient.publish(channel, json, function (err) {
-      if (err != null) {
+    pubsubClient.publish(channel, json, function (err) {
+      if (err) {
         logger.err({ err, channel }, 'error publishing pubsub traffic to redis')
       }
       const blob = JSON.stringify({ keep: 'alive' })
       Metrics.summary('redis.publish.cluster-continual-traffic', blob.length)
-      return clusterClient.publish('cluster-continual-traffic', blob, callback)
+      clusterClient.publish('cluster-continual-traffic', blob, callback)
     })
   }
 
-  var runPubSubTraffic = () =>
+  const runPubSubTraffic = () =>
     async.map(['applied-ops', 'editor-events'], publishJob, () =>
       setTimeout(runPubSubTraffic, 1000 * 20)
     )
 
   runPubSubTraffic()
 }
-
-function __guard__(value, transform) {
-  return typeof value !== 'undefined' && value !== null
-    ? transform(value)
-    : undefined
-}
diff --git a/services/real-time/app/js/AuthorizationManager.js b/services/real-time/app/js/AuthorizationManager.js
index 15607a898a..a545594479 100644
--- a/services/real-time/app/js/AuthorizationManager.js
+++ b/services/real-time/app/js/AuthorizationManager.js
@@ -1,23 +1,10 @@
 /* eslint-disable
     camelcase,
-    handle-callback-err,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS102: Remove unnecessary code created because of implicit returns
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
 let AuthorizationManager
 module.exports = AuthorizationManager = {
   assertClientCanViewProject(client, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
-    return AuthorizationManager._assertClientHasPrivilegeLevel(
+    AuthorizationManager._assertClientHasPrivilegeLevel(
       client,
       ['readOnly', 'readAndWrite', 'owner'],
       callback
@@ -25,10 +12,7 @@ module.exports = AuthorizationManager = {
   },
 
   assertClientCanEditProject(client, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
-    return AuthorizationManager._assertClientHasPrivilegeLevel(
+    AuthorizationManager._assertClientHasPrivilegeLevel(
       client,
       ['readAndWrite', 'owner'],
       callback
@@ -36,76 +20,46 @@ module.exports = AuthorizationManager = {
   },
 
   _assertClientHasPrivilegeLevel(client, allowedLevels, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
-    if (Array.from(allowedLevels).includes(client.ol_context.privilege_level)) {
-      return callback(null)
+    if (allowedLevels.includes(client.ol_context.privilege_level)) {
+      callback(null)
     } else {
-      return callback(new Error('not authorized'))
+      callback(new Error('not authorized'))
     }
   },
 
   assertClientCanViewProjectAndDoc(client, doc_id, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
-    return AuthorizationManager.assertClientCanViewProject(client, function (
-      error
-    ) {
-      if (error != null) {
+    AuthorizationManager.assertClientCanViewProject(client, function (error) {
+      if (error) {
         return callback(error)
       }
-      return AuthorizationManager._assertClientCanAccessDoc(
-        client,
-        doc_id,
-        callback
-      )
+      AuthorizationManager._assertClientCanAccessDoc(client, doc_id, callback)
     })
   },
 
   assertClientCanEditProjectAndDoc(client, doc_id, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
-    return AuthorizationManager.assertClientCanEditProject(client, function (
-      error
-    ) {
-      if (error != null) {
+    AuthorizationManager.assertClientCanEditProject(client, function (error) {
+      if (error) {
         return callback(error)
       }
-      return AuthorizationManager._assertClientCanAccessDoc(
-        client,
-        doc_id,
-        callback
-      )
+      AuthorizationManager._assertClientCanAccessDoc(client, doc_id, callback)
     })
   },
 
   _assertClientCanAccessDoc(client, doc_id, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
     if (client.ol_context[`doc:${doc_id}`] === 'allowed') {
-      return callback(null)
+      callback(null)
     } else {
-      return callback(new Error('not authorized'))
+      callback(new Error('not authorized'))
     }
   },
 
   addAccessToDoc(client, doc_id, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
     client.ol_context[`doc:${doc_id}`] = 'allowed'
-    return callback(null)
+    callback(null)
   },
 
   removeAccessToDoc(client, doc_id, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
     delete client.ol_context[`doc:${doc_id}`]
-    return callback(null)
+    callback(null)
   }
 }
diff --git a/services/real-time/app/js/ChannelManager.js b/services/real-time/app/js/ChannelManager.js
index 09e81cebf5..e84cfe44a9 100644
--- a/services/real-time/app/js/ChannelManager.js
+++ b/services/real-time/app/js/ChannelManager.js
@@ -1,14 +1,3 @@
-/* eslint-disable
-    no-unused-vars,
-*/
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let ChannelManager
 const logger = require('logger-sharelatex')
 const metrics = require('metrics-sharelatex')
 const settings = require('settings-sharelatex')
@@ -19,7 +8,7 @@ const ClientMap = new Map() // for each redis client, store a Map of subscribed
 // that we never subscribe to a channel multiple times. The socket.io side is
 // handled by RoomManager.
 
-module.exports = ChannelManager = {
+module.exports = {
   getClientMapEntry(rclient) {
     // return the per-client channel map if it exists, otherwise create and
     // return an empty map for the client.
@@ -36,22 +25,25 @@ module.exports = ChannelManager = {
       const p = rclient.subscribe(channel)
       p.finally(function () {
         if (clientChannelMap.get(channel) === subscribePromise) {
-          return clientChannelMap.delete(channel)
+          clientChannelMap.delete(channel)
         }
       })
         .then(function () {
           logger.log({ channel }, 'subscribed to channel')
-          return metrics.inc(`subscribe.${baseChannel}`)
+          metrics.inc(`subscribe.${baseChannel}`)
         })
         .catch(function (err) {
           logger.error({ channel, err }, 'failed to subscribe to channel')
-          return metrics.inc(`subscribe.failed.${baseChannel}`)
+          metrics.inc(`subscribe.failed.${baseChannel}`)
         })
       return p
     }
 
     const pendingActions = clientChannelMap.get(channel) || Promise.resolve()
-    var subscribePromise = pendingActions.then(actualSubscribe, actualSubscribe)
+    const subscribePromise = pendingActions.then(
+      actualSubscribe,
+      actualSubscribe
+    )
     clientChannelMap.set(channel, subscribePromise)
     logger.log({ channel }, 'planned to subscribe to channel')
     return subscribePromise
@@ -62,26 +54,25 @@ module.exports = ChannelManager = {
     const channel = `${baseChannel}:${id}`
     const actualUnsubscribe = function () {
       // unsubscribe is happening in the background, it should not reject
-      const p = rclient
+      return rclient
         .unsubscribe(channel)
         .finally(function () {
           if (clientChannelMap.get(channel) === unsubscribePromise) {
-            return clientChannelMap.delete(channel)
+            clientChannelMap.delete(channel)
           }
         })
         .then(function () {
           logger.log({ channel }, 'unsubscribed from channel')
-          return metrics.inc(`unsubscribe.${baseChannel}`)
+          metrics.inc(`unsubscribe.${baseChannel}`)
         })
         .catch(function (err) {
           logger.error({ channel, err }, 'unsubscribed from channel')
-          return metrics.inc(`unsubscribe.failed.${baseChannel}`)
+          metrics.inc(`unsubscribe.failed.${baseChannel}`)
         })
-      return p
     }
 
     const pendingActions = clientChannelMap.get(channel) || Promise.resolve()
-    var unsubscribePromise = pendingActions.then(
+    const unsubscribePromise = pendingActions.then(
       actualUnsubscribe,
       actualUnsubscribe
     )
@@ -100,6 +91,6 @@ module.exports = ChannelManager = {
     }
     // we publish on a different client to the subscribe, so we can't
     // check for the channel existing here
-    return rclient.publish(channel, data)
+    rclient.publish(channel, data)
   }
 }
diff --git a/services/real-time/app/js/ConnectedUsersManager.js b/services/real-time/app/js/ConnectedUsersManager.js
index 6770dd5421..06ea442d63 100644
--- a/services/real-time/app/js/ConnectedUsersManager.js
+++ b/services/real-time/app/js/ConnectedUsersManager.js
@@ -1,15 +1,6 @@
 /* eslint-disable
     camelcase,
-    handle-callback-err,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
 const async = require('async')
 const Settings = require('settings-sharelatex')
 const logger = require('logger-sharelatex')
@@ -29,9 +20,6 @@ module.exports = {
   // update. This way we don't care if the connected_user key has expired when
   // we receive a cursor update.
   updateUserPosition(project_id, client_id, user, cursorData, callback) {
-    if (callback == null) {
-      callback = function (err) {}
-    }
     logger.log({ project_id, client_id }, 'marking user as joined or connected')
 
     const multi = rclient.multi()
@@ -65,7 +53,7 @@ module.exports = {
       user.email || ''
     )
 
-    if (cursorData != null) {
+    if (cursorData) {
       multi.hset(
         Keys.connectedUser({ project_id, client_id }),
         'cursorData',
@@ -77,21 +65,18 @@ module.exports = {
       USER_TIMEOUT_IN_S
     )
 
-    return multi.exec(function (err) {
-      if (err != null) {
+    multi.exec(function (err) {
+      if (err) {
         logger.err(
           { err, project_id, client_id },
           'problem marking user as connected'
         )
       }
-      return callback(err)
+      callback(err)
     })
   },
 
-  refreshClient(project_id, client_id, callback) {
-    if (callback == null) {
-      callback = function (err) {}
-    }
+  refreshClient(project_id, client_id) {
     logger.log({ project_id, client_id }, 'refreshing connected client')
     const multi = rclient.multi()
     multi.hset(
@@ -103,14 +88,13 @@ module.exports = {
       Keys.connectedUser({ project_id, client_id }),
       USER_TIMEOUT_IN_S
     )
-    return multi.exec(function (err) {
-      if (err != null) {
+    multi.exec(function (err) {
+      if (err) {
         logger.err(
           { err, project_id, client_id },
           'problem refreshing connected client'
         )
       }
-      return callback(err)
     })
   },
 
@@ -120,74 +104,66 @@ module.exports = {
     multi.srem(Keys.clientsInProject({ project_id }), client_id)
     multi.expire(Keys.clientsInProject({ project_id }), FOUR_DAYS_IN_S)
     multi.del(Keys.connectedUser({ project_id, client_id }))
-    return multi.exec(callback)
+    multi.exec(callback)
   },
 
   _getConnectedUser(project_id, client_id, callback) {
-    return rclient.hgetall(
-      Keys.connectedUser({ project_id, client_id }),
-      function (err, result) {
-        if (
-          result == null ||
-          Object.keys(result).length === 0 ||
-          !result.user_id
-        ) {
-          result = {
-            connected: false,
-            client_id
-          }
-        } else {
-          result.connected = true
-          result.client_id = client_id
-          result.client_age =
-            (Date.now() - parseInt(result.last_updated_at, 10)) / 1000
-          if (result.cursorData != null) {
-            try {
-              result.cursorData = JSON.parse(result.cursorData)
-            } catch (e) {
-              logger.error(
-                {
-                  err: e,
-                  project_id,
-                  client_id,
-                  cursorData: result.cursorData
-                },
-                'error parsing cursorData JSON'
-              )
-              return callback(e)
-            }
+    rclient.hgetall(Keys.connectedUser({ project_id, client_id }), function (
+      err,
+      result
+    ) {
+      if (!(result && result.user_id)) {
+        result = {
+          connected: false,
+          client_id
+        }
+      } else {
+        result.connected = true
+        result.client_id = client_id
+        result.client_age =
+          (Date.now() - parseInt(result.last_updated_at, 10)) / 1000
+        if (result.cursorData) {
+          try {
+            result.cursorData = JSON.parse(result.cursorData)
+          } catch (e) {
+            logger.error(
+              {
+                err: e,
+                project_id,
+                client_id,
+                cursorData: result.cursorData
+              },
+              'error parsing cursorData JSON'
+            )
+            return callback(e)
           }
         }
-        return callback(err, result)
       }
-    )
+      callback(err, result)
+    })
   },
 
   getConnectedUsers(project_id, callback) {
     const self = this
-    return rclient.smembers(Keys.clientsInProject({ project_id }), function (
+    rclient.smembers(Keys.clientsInProject({ project_id }), function (
       err,
       results
     ) {
-      if (err != null) {
+      if (err) {
         return callback(err)
       }
       const jobs = results.map((client_id) => (cb) =>
         self._getConnectedUser(project_id, client_id, cb)
       )
-      return async.series(jobs, function (err, users) {
-        if (users == null) {
-          users = []
-        }
-        if (err != null) {
+      async.series(jobs, function (err, users) {
+        if (err) {
           return callback(err)
         }
         users = users.filter(
           (user) =>
-            (user != null ? user.connected : undefined) &&
-            (user != null ? user.client_age : undefined) < REFRESH_TIMEOUT_IN_S
+            user && user.connected && user.client_age < REFRESH_TIMEOUT_IN_S
         )
-        return callback(null, users)
+        callback(null, users)
       })
     })
   }
diff --git a/services/real-time/app/js/DocumentUpdaterController.js b/services/real-time/app/js/DocumentUpdaterController.js
index b8dde3b426..bf8d25ae85 100644
--- a/services/real-time/app/js/DocumentUpdaterController.js
+++ b/services/real-time/app/js/DocumentUpdaterController.js
@@ -1,18 +1,6 @@
 /* eslint-disable
     camelcase,
-    no-unused-vars,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS102: Remove unnecessary code created because of implicit returns
- * DS205: Consider reworking code to avoid use of IIFEs
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let DocumentUpdaterController
 const logger = require('logger-sharelatex')
 const settings = require('settings-sharelatex')
 const RedisClientManager = require('./RedisClientManager')
@@ -23,28 +11,25 @@ const RoomManager = require('./RoomManager')
 const ChannelManager = require('./ChannelManager')
 const metrics = require('metrics-sharelatex')
 
-const MESSAGE_SIZE_LOG_LIMIT = 1024 * 1024 // 1Mb
-
+let DocumentUpdaterController
 module.exports = DocumentUpdaterController = {
   // DocumentUpdaterController is responsible for updates that come via Redis
   // Pub/Sub from the document updater.
   rclientList: RedisClientManager.createClientList(settings.redis.pubsub),
 
   listenForUpdatesFromDocumentUpdater(io) {
-    let i, rclient
     logger.log(
       { rclients: this.rclientList.length },
       'listening for applied-ops events'
     )
-    for (i = 0; i < this.rclientList.length; i++) {
-      rclient = this.rclientList[i]
+    for (const rclient of this.rclientList) {
       rclient.subscribe('applied-ops')
       rclient.on('message', function (channel, message) {
         metrics.inc('rclient', 0.001) // global event rate metric
         if (settings.debugEvents > 0) {
           EventLogger.debugEvent(channel, message)
         }
-        return DocumentUpdaterController._processMessageFromDocumentUpdater(
+        DocumentUpdaterController._processMessageFromDocumentUpdater(
           io,
           channel,
           message
@@ -53,42 +38,41 @@ module.exports = DocumentUpdaterController = {
     }
     // create metrics for each redis instance only when we have multiple redis clients
     if (this.rclientList.length > 1) {
-      for (i = 0; i < this.rclientList.length; i++) {
-        rclient = this.rclientList[i]
-        ;((
-          i // per client event rate metric
-        ) => rclient.on('message', () => metrics.inc(`rclient-${i}`, 0.001)))(i)
-      }
+      this.rclientList.forEach((rclient, i) => {
+        // per client event rate metric
+        const metricName = `rclient-${i}`
+        rclient.on('message', () => metrics.inc(metricName, 0.001))
+      })
     }
-    return this.handleRoomUpdates(this.rclientList)
+    this.handleRoomUpdates(this.rclientList)
   },
 
   handleRoomUpdates(rclientSubList) {
     const roomEvents = RoomManager.eventSource()
     roomEvents.on('doc-active', function (doc_id) {
-      const subscribePromises = Array.from(rclientSubList).map((rclient) =>
+      const subscribePromises = rclientSubList.map((rclient) =>
         ChannelManager.subscribe(rclient, 'applied-ops', doc_id)
       )
-      return RoomManager.emitOnCompletion(
+      RoomManager.emitOnCompletion(
         subscribePromises,
         `doc-subscribed-${doc_id}`
       )
     })
-    return roomEvents.on('doc-empty', (doc_id) =>
-      Array.from(rclientSubList).map((rclient) =>
+    roomEvents.on('doc-empty', (doc_id) =>
+      rclientSubList.map((rclient) =>
         ChannelManager.unsubscribe(rclient, 'applied-ops', doc_id)
       )
     )
   },
 
   _processMessageFromDocumentUpdater(io, channel, message) {
-    return SafeJsonParse.parse(message, function (error, message) {
-      if (error != null) {
+    SafeJsonParse.parse(message, function (error, message) {
+      if (error) {
         logger.error({ err: error, channel }, 'error parsing JSON')
         return
       }
-      if (message.op != null) {
-        if (message._id != null && settings.checkEventOrder) {
+      if (message.op) {
+        if (message._id && settings.checkEventOrder) {
           const status = EventLogger.checkEventOrder(
             'applied-ops',
             message._id,
@@ -98,24 +82,24 @@ module.exports = DocumentUpdaterController = {
             return // skip duplicate events
           }
         }
-        return DocumentUpdaterController._applyUpdateFromDocumentUpdater(
+        DocumentUpdaterController._applyUpdateFromDocumentUpdater(
           io,
           message.doc_id,
           message.op
         )
-      } else if (message.error != null) {
-        return DocumentUpdaterController._processErrorFromDocumentUpdater(
+      } else if (message.error) {
+        DocumentUpdaterController._processErrorFromDocumentUpdater(
           io,
           message.doc_id,
           message.error,
           message
         )
-      } else if (message.health_check != null) {
+      } else if (message.health_check) {
         logger.debug(
           { message },
           'got health check message in applied ops channel'
         )
-        return HealthCheckManager.check(channel, message.key)
+        HealthCheckManager.check(channel, message.key)
       }
     })
   },
@@ -132,20 +116,14 @@ module.exports = DocumentUpdaterController = {
       {
         doc_id,
         version: update.v,
-        source: update.meta != null ? update.meta.source : undefined,
-        socketIoClients: (() => {
-          const result = []
-          for (client of Array.from(clientList)) {
-            result.push(client.id)
-          }
-          return result
-        })()
+        source: update.meta && update.meta.source,
+        socketIoClients: clientList.map((client) => client.id)
       },
       'distributing updates to clients'
     )
     const seen = {}
     // send messages only to unique clients (due to duplicate entries in io.sockets.clients)
-    for (client of Array.from(clientList)) {
+    for (client of clientList) {
       if (!seen[client.id]) {
         seen[client.id] = true
         if (client.publicId === update.meta.source) {
@@ -153,7 +131,7 @@ module.exports = DocumentUpdaterController = {
             {
               doc_id,
               version: update.v,
-              source: update.meta != null ? update.meta.source : undefined
+              source: update.meta.source
             },
             'distributing update to sender'
           )
@@ -164,7 +142,7 @@ module.exports = DocumentUpdaterController = {
             {
               doc_id,
               version: update.v,
-              source: update.meta != null ? update.meta.source : undefined,
+              source: update.meta.source,
               client_id: client.id
             },
             'distributing update to collaborator'
@@ -175,16 +153,10 @@ module.exports = DocumentUpdaterController = {
     }
     if (Object.keys(seen).length < clientList.length) {
       metrics.inc('socket-io.duplicate-clients', 0.1)
-      return logger.log(
+      logger.log(
         {
           doc_id,
-          socketIoClients: (() => {
-            const result1 = []
-            for (client of Array.from(clientList)) {
-              result1.push(client.id)
-            }
-            return result1
-          })()
+          socketIoClients: clientList.map((client) => client.id)
         },
         'discarded duplicate clients'
       )
@@ -192,17 +164,13 @@ module.exports = DocumentUpdaterController = {
   },
 
   _processErrorFromDocumentUpdater(io, doc_id, error, message) {
-    return (() => {
-      const result = []
-      for (const client of Array.from(io.sockets.clients(doc_id))) {
-        logger.warn(
-          { err: error, doc_id, client_id: client.id },
-          'error from document updater, disconnecting client'
-        )
-        client.emit('otUpdateError', error, message)
-        result.push(client.disconnect())
-      }
-      return result
-    })()
+    for (const client of io.sockets.clients(doc_id)) {
+      logger.warn(
+        { err: error, doc_id, client_id: client.id },
+        'error from document updater, disconnecting client'
+      )
+      client.emit('otUpdateError', error, message)
+      client.disconnect()
+    }
   }
 }
diff --git a/services/real-time/app/js/DocumentUpdaterManager.js b/services/real-time/app/js/DocumentUpdaterManager.js
index bafc81ed14..32533a9eaa 100644
--- a/services/real-time/app/js/DocumentUpdaterManager.js
+++ b/services/real-time/app/js/DocumentUpdaterManager.js
@@ -1,17 +1,6 @@
 /* eslint-disable
     camelcase,
-    handle-callback-err,
-    no-unused-vars,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let DocumentUpdaterManager
 const request = require('request')
 const _ = require('underscore')
 const logger = require('logger-sharelatex')
@@ -23,20 +12,17 @@ const rclient = require('redis-sharelatex').createClient(
 )
 const Keys = settings.redis.documentupdater.key_schema
 
-module.exports = DocumentUpdaterManager = {
+module.exports = {
   getDocument(project_id, doc_id, fromVersion, callback) {
-    if (callback == null) {
-      callback = function (error, exists, doclines, version) {}
-    }
     const timer = new metrics.Timer('get-document')
     const url = `${settings.apis.documentupdater.url}/project/${project_id}/doc/${doc_id}?fromVersion=${fromVersion}`
     logger.log(
       { project_id, doc_id, fromVersion },
       'getting doc from document updater'
     )
-    return request.get(url, function (err, res, body) {
+    request.get(url, function (err, res, body) {
       timer.done()
-      if (err != null) {
+      if (err) {
         logger.error(
           { err, url, project_id, doc_id },
           'error getting doc from doc updater'
@@ -53,13 +39,8 @@ module.exports = DocumentUpdaterManager = {
         } catch (error) {
           return callback(error)
         }
-        return callback(
-          null,
-          body != null ? body.lines : undefined,
-          body != null ? body.version : undefined,
-          body != null ? body.ranges : undefined,
-          body != null ? body.ops : undefined
-        )
+        body = body || {}
+        callback(null, body.lines, body.version, body.ranges, body.ops)
       } else if ([404, 422].includes(res.statusCode)) {
         err = new Error('doc updater could not load requested ops')
         err.statusCode = res.statusCode
@@ -67,7 +48,7 @@ module.exports = DocumentUpdaterManager = {
           { err, project_id, doc_id, url, fromVersion },
           'doc updater could not load requested ops'
         )
-        return callback(err)
+        callback(err)
       } else {
         err = new Error(
           `doc updater returned a non-success status code: ${res.statusCode}`
@@ -77,33 +58,30 @@ module.exports = DocumentUpdaterManager = {
           { err, project_id, doc_id, url },
           `doc updater returned a non-success status code: ${res.statusCode}`
         )
-        return callback(err)
+        callback(err)
       }
     })
   },
 
   flushProjectToMongoAndDelete(project_id, callback) {
     // this method is called when the last connected user leaves the project
-    if (callback == null) {
-      callback = function () {}
-    }
     logger.log({ project_id }, 'deleting project from document updater')
     const timer = new metrics.Timer('delete.mongo.project')
     // flush the project in the background when all users have left
     const url =
       `${settings.apis.documentupdater.url}/project/${project_id}?background=true` +
       (settings.shutDownInProgress ? '&shutdown=true' : '')
-    return request.del(url, function (err, res, body) {
+    request.del(url, function (err, res) {
       timer.done()
-      if (err != null) {
+      if (err) {
         logger.error(
           { err, project_id },
           'error deleting project from document updater'
         )
-        return callback(err)
+        callback(err)
       } else if (res.statusCode >= 200 && res.statusCode < 300) {
         logger.log({ project_id }, 'deleted project from document updater')
-        return callback(null)
+        callback(null)
       } else {
         err = new Error(
           `document updater returned a failure status code: ${res.statusCode}`
@@ -113,16 +91,12 @@ module.exports = DocumentUpdaterManager = {
           { err, project_id },
           `document updater returned failure status code: ${res.statusCode}`
         )
-        return callback(err)
+        callback(err)
       }
     })
   },
 
   queueChange(project_id, doc_id, change, callback) {
-    let error
-    if (callback == null) {
-      callback = function () {}
-    }
     const allowedKeys = [
       'doc',
       'op',
@@ -136,7 +110,7 @@ module.exports = DocumentUpdaterManager = {
     const jsonChange = JSON.stringify(change)
     if (jsonChange.indexOf('\u0000') !== -1) {
       // memory corruption check
-      error = new Error('null bytes found in op')
+      const error = new Error('null bytes found in op')
       logger.error(
         { err: error, project_id, doc_id, jsonChange },
         error.message
@@ -146,7 +120,7 @@ module.exports = DocumentUpdaterManager = {
 
     const updateSize = jsonChange.length
     if (updateSize > settings.maxUpdateSize) {
-      error = new Error('update is too large')
+      const error = new Error('update is too large')
       error.updateSize = updateSize
       return callback(error)
     }
@@ -157,13 +131,13 @@ module.exports = DocumentUpdaterManager = {
     const doc_key = `${project_id}:${doc_id}`
     // Push onto pendingUpdates for doc_id first, because once the doc updater
     // gets an entry on pending-updates-list, it starts processing.
-    return rclient.rpush(Keys.pendingUpdates({ doc_id }), jsonChange, function (
+    rclient.rpush(Keys.pendingUpdates({ doc_id }), jsonChange, function (
       error
     ) {
-      if (error != null) {
+      if (error) {
         return callback(error)
       }
-      return rclient.rpush('pending-updates-list', doc_key, callback)
+      rclient.rpush('pending-updates-list', doc_key, callback)
     })
   }
 }
diff --git a/services/real-time/app/js/DrainManager.js b/services/real-time/app/js/DrainManager.js
index b8c08356bb..c605957160 100644
--- a/services/real-time/app/js/DrainManager.js
+++ b/services/real-time/app/js/DrainManager.js
@@ -1,31 +1,21 @@
-/* eslint-disable
-    no-return-assign,
-*/
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS102: Remove unnecessary code created because of implicit returns
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let DrainManager
 const logger = require('logger-sharelatex')
 
-module.exports = DrainManager = {
+module.exports = {
   startDrainTimeWindow(io, minsToDrain) {
     const drainPerMin = io.sockets.clients().length / minsToDrain
-    return DrainManager.startDrain(io, Math.max(drainPerMin / 60, 4))
-  }, // enforce minimum drain rate
+    // enforce minimum drain rate
+    this.startDrain(io, Math.max(drainPerMin / 60, 4))
+  },
 
   startDrain(io, rate) {
     // Clear out any old interval
-    let pollingInterval
     clearInterval(this.interval)
     logger.log({ rate }, 'starting drain')
     if (rate === 0) {
       return
-    } else if (rate < 1) {
+    }
+    let pollingInterval
+    if (rate < 1) {
       // allow lower drain rates
       // e.g. rate=0.1 will drain one client every 10 seconds
       pollingInterval = 1000 / rate
@@ -33,15 +23,15 @@ module.exports = DrainManager = {
     } else {
       pollingInterval = 1000
     }
-    return (this.interval = setInterval(() => {
-      return this.reconnectNClients(io, rate)
-    }, pollingInterval))
+    this.interval = setInterval(() => {
+      this.reconnectNClients(io, rate)
+    }, pollingInterval)
   },
 
   RECONNECTED_CLIENTS: {},
   reconnectNClients(io, N) {
     let drainedCount = 0
-    for (const client of Array.from(io.sockets.clients())) {
+    for (const client of io.sockets.clients()) {
       if (!this.RECONNECTED_CLIENTS[client.id]) {
         this.RECONNECTED_CLIENTS[client.id] = true
         logger.log(
@@ -57,7 +47,7 @@ module.exports = DrainManager = {
       }
     }
     if (drainedCount < N) {
-      return logger.log('All clients have been told to reconnectGracefully')
+      logger.log('All clients have been told to reconnectGracefully')
     }
   }
 }
diff --git a/services/real-time/app/js/Errors.js b/services/real-time/app/js/Errors.js
index 8bfe3763b0..bdda1b4c21 100644
--- a/services/real-time/app/js/Errors.js
+++ b/services/real-time/app/js/Errors.js
@@ -1,17 +1,9 @@
-/* eslint-disable
-    no-proto,
-    no-unused-vars,
-*/
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-let Errors
-var CodedError = function (message, code) {
-  const error = new Error(message)
-  error.name = 'CodedError'
-  error.code = code
-  error.__proto__ = CodedError.prototype
-  return error
+class CodedError extends Error {
+  constructor(message, code) {
+    super(message)
+    this.name = this.constructor.name
+    this.code = code
+  }
 }
-CodedError.prototype.__proto__ = Error.prototype
 
-module.exports = Errors = { CodedError }
+module.exports = { CodedError }
diff --git a/services/real-time/app/js/EventLogger.js b/services/real-time/app/js/EventLogger.js
index 1133ebdaf8..9db3f8aa55 100644
--- a/services/real-time/app/js/EventLogger.js
+++ b/services/real-time/app/js/EventLogger.js
@@ -1,15 +1,6 @@
 /* eslint-disable
     camelcase,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * DS205: Consider reworking code to avoid use of IIFEs
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
 let EventLogger
 const logger = require('logger-sharelatex')
 const metrics = require('metrics-sharelatex')
@@ -31,15 +22,15 @@ module.exports = EventLogger = {
   debugEvent(channel, message) {
     if (settings.debugEvents > 0) {
       logger.log({ channel, message, counter: COUNTER++ }, 'logging event')
-      return settings.debugEvents--
+      settings.debugEvents--
     }
   },
 
-  checkEventOrder(channel, message_id, message) {
-    let result
+  checkEventOrder(channel, message_id) {
     if (typeof message_id !== 'string') {
       return
     }
+    let result
     if (!(result = message_id.match(/^(.*)-(\d+)$/))) {
       return
     }
@@ -51,7 +42,7 @@ module.exports = EventLogger = {
     }
     // store the last count in a hash for each host
     const previous = EventLogger._storeEventCount(key, count)
-    if (previous == null || count === previous + 1) {
+    if (!previous || count === previous + 1) {
       metrics.inc(`event.${channel}.valid`, 0.001) // downsample high rate docupdater events
       return // order is ok
     }
@@ -83,18 +74,11 @@ module.exports = EventLogger = {
   },
 
   _cleanEventStream(now) {
-    return (() => {
-      const result = []
-      for (const key in EVENT_LOG_TIMESTAMP) {
-        const timestamp = EVENT_LOG_TIMESTAMP[key]
-        if (now - timestamp > EventLogger.MAX_STALE_TIME_IN_MS) {
-          delete EVENT_LOG_COUNTER[key]
-          result.push(delete EVENT_LOG_TIMESTAMP[key])
-        } else {
-          result.push(undefined)
-        }
+    Object.entries(EVENT_LOG_TIMESTAMP).forEach(([key, timestamp]) => {
+      if (now - timestamp > EventLogger.MAX_STALE_TIME_IN_MS) {
+        delete EVENT_LOG_COUNTER[key]
+        delete EVENT_LOG_TIMESTAMP[key]
       }
-      return result
-    })()
+    })
   }
 }
diff --git a/services/real-time/app/js/HealthCheckManager.js b/services/real-time/app/js/HealthCheckManager.js
index 4704aa5e88..a297807fe8 100644
--- a/services/real-time/app/js/HealthCheckManager.js
+++ b/services/real-time/app/js/HealthCheckManager.js
@@ -1,16 +1,3 @@
-/* eslint-disable
-    no-return-assign,
-    no-unused-vars,
-*/
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let HealthCheckManager
 const metrics = require('metrics-sharelatex')
 const logger = require('logger-sharelatex')
 
@@ -22,22 +9,19 @@ let COUNT = 0
 const CHANNEL_MANAGER = {} // hash of event checkers by channel name
 const CHANNEL_ERROR = {} // error status by channel name
 
-module.exports = HealthCheckManager = class HealthCheckManager {
+module.exports = class HealthCheckManager {
   // create an instance of this class which checks that an event with a unique
   // id is received only once within a timeout
   constructor(channel, timeout) {
     // unique event string
     this.channel = channel
-    if (timeout == null) {
-      timeout = 1000
-    }
     this.id = `host=${HOST}:pid=${PID}:count=${COUNT++}`
     // count of number of times the event is received
     this.count = 0
     // after a timeout check the status of the count
     this.handler = setTimeout(() => {
-      return this.setStatus()
-    }, timeout)
+      this.setStatus()
+    }, timeout || 1000)
     // use a timer to record the latency of the channel
     this.timer = new metrics.Timer(`event.${this.channel}.latency`)
     // keep a record of these objects to dispatch on
@@ -48,31 +32,31 @@ module.exports = HealthCheckManager = class HealthCheckManager {
     // if this is our event record it
     if (id === this.id) {
       this.count++
-      if (this.timer != null) {
+      if (this.timer) {
         this.timer.done()
       }
-      return (this.timer = null) // only time the latency of the first event
+      this.timer = undefined // only time the latency of the first event
     }
   }
 
   setStatus() {
     // if we saw the event anything other than a single time that is an error
-    if (this.count !== 1) {
+    const isFailing = this.count !== 1
+    if (isFailing) {
       logger.err(
         { channel: this.channel, count: this.count, id: this.id },
         'redis channel health check error'
       )
     }
-    const error = this.count !== 1
-    return (CHANNEL_ERROR[this.channel] = error)
+    CHANNEL_ERROR[this.channel] = isFailing
   }
 
   // class methods
   static check(channel, id) {
     // dispatch event to manager for channel
-    return CHANNEL_MANAGER[channel] != null
-      ? CHANNEL_MANAGER[channel].processEvent(id)
-      : undefined
+    if (CHANNEL_MANAGER[channel]) {
+      CHANNEL_MANAGER[channel].processEvent(id)
+    }
   }
 
   static status() {
diff --git a/services/real-time/app/js/HttpApiController.js b/services/real-time/app/js/HttpApiController.js
index a512961797..7b9627fd7b 100644
--- a/services/real-time/app/js/HttpApiController.js
+++ b/services/real-time/app/js/HttpApiController.js
@@ -1,25 +1,15 @@
 /* eslint-disable
     camelcase,
-    no-unused-vars,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS102: Remove unnecessary code created because of implicit returns
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let HttpApiController
 const WebsocketLoadBalancer = require('./WebsocketLoadBalancer')
 const DrainManager = require('./DrainManager')
 const logger = require('logger-sharelatex')
 
-module.exports = HttpApiController = {
-  sendMessage(req, res, next) {
+module.exports = {
+  sendMessage(req, res) {
     logger.log({ message: req.params.message }, 'sending message')
     if (Array.isArray(req.body)) {
-      for (const payload of Array.from(req.body)) {
+      for (const payload of req.body) {
         WebsocketLoadBalancer.emitToRoom(
           req.params.project_id,
           req.params.message,
@@ -33,16 +23,16 @@ module.exports = HttpApiController = {
         req.body
       )
     }
-    return res.send(204)
-  }, // No content
+    res.send(204)
+  },
 
-  startDrain(req, res, next) {
+  startDrain(req, res) {
     const io = req.app.get('io')
     let rate = req.query.rate || '4'
     rate = parseFloat(rate) || 0
     logger.log({ rate }, 'setting client drain rate')
     DrainManager.startDrain(io, rate)
-    return res.send(204)
+    res.send(204)
   },
 
   disconnectClient(req, res, next) {
@@ -57,6 +47,6 @@ module.exports = HttpApiController = {
     }
     logger.warn({ client_id }, 'api: requesting client disconnect')
     client.on('disconnect', () => res.sendStatus(204))
-    return client.disconnect()
+    client.disconnect()
   }
 }
diff --git a/services/real-time/app/js/HttpController.js b/services/real-time/app/js/HttpController.js
index deabf5876d..68e5d4cd07 100644
--- a/services/real-time/app/js/HttpController.js
+++ b/services/real-time/app/js/HttpController.js
@@ -1,28 +1,15 @@
 /* eslint-disable
     camelcase,
-    handle-callback-err,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let HttpController
-const async = require('async')
 
+let HttpController
 module.exports = HttpController = {
   // The code in this controller is hard to unit test because of a lot of
   // dependencies on internal socket.io methods. It is not critical to the running
   // of ShareLaTeX, and is only used for getting stats about connected clients,
   // and for checking internal state in acceptance tests. The acceptances tests
   // should provide appropriate coverage.
-  _getConnectedClientView(ioClient, callback) {
-    if (callback == null) {
-      callback = function (error, client) {}
-    }
+  _getConnectedClientView(ioClient) {
     const client_id = ioClient.id
     const {
       project_id,
@@ -41,32 +28,23 @@ module.exports = HttpController = {
       email,
       connected_time
     }
-    client.rooms = []
-    for (const name in ioClient.manager.roomClients[client_id]) {
-      const joined = ioClient.manager.roomClients[client_id][name]
-      if (joined && name !== '') {
-        client.rooms.push(name.replace(/^\//, '')) // Remove leading /
-      }
-    }
-    return callback(null, client)
+    client.rooms = Object.keys(ioClient.manager.roomClients[client_id] || {})
+      // drop the namespace
+      .filter((room) => room !== '')
+      // room names are composed as '<NAMESPACE>/<ROOM>' and the default
+      //  namespace is empty (see comments in RoomManager), just drop the '/'
+      .map((fullRoomPath) => fullRoomPath.slice(1))
+    return client
   },
 
-  getConnectedClients(req, res, next) {
+  getConnectedClients(req, res) {
     const io = req.app.get('io')
     const ioClients = io.sockets.clients()
-    return async.map(
-      ioClients,
-      HttpController._getConnectedClientView,
-      function (error, clients) {
-        if (error != null) {
-          return next(error)
-        }
-        return res.json(clients)
-      }
-    )
+
+    res.json(ioClients.map(HttpController._getConnectedClientView))
   },
 
-  getConnectedClient(req, res, next) {
+  getConnectedClient(req, res) {
     const { client_id } = req.params
     const io = req.app.get('io')
     const ioClient = io.sockets.sockets[client_id]
@@ -74,14 +52,6 @@ module.exports = HttpController = {
       res.sendStatus(404)
       return
     }
-    return HttpController._getConnectedClientView(ioClient, function (
-      error,
-      client
-    ) {
-      if (error != null) {
-        return next(error)
-      }
-      return res.json(client)
-    })
+    res.json(HttpController._getConnectedClientView(ioClient))
   }
 }
diff --git a/services/real-time/app/js/RedisClientManager.js b/services/real-time/app/js/RedisClientManager.js
index b43262aeda..d05cc64818 100644
--- a/services/real-time/app/js/RedisClientManager.js
+++ b/services/real-time/app/js/RedisClientManager.js
@@ -1,40 +1,19 @@
-/* eslint-disable
-    no-unused-vars,
-*/
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS205: Consider reworking code to avoid use of IIFEs
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let RedisClientManager
 const redis = require('redis-sharelatex')
 const logger = require('logger-sharelatex')
 
-module.exports = RedisClientManager = {
+module.exports = {
   createClientList(...configs) {
     // create a dynamic list of redis clients, excluding any configurations which are not defined
-    const clientList = (() => {
-      const result = []
-      for (const x of Array.from(configs)) {
-        if (x != null) {
-          const redisType =
-            x.cluster != null
-              ? 'cluster'
-              : x.sentinels != null
-              ? 'sentinel'
-              : x.host != null
-              ? 'single'
-              : 'unknown'
-          logger.log({ redis: redisType }, 'creating redis client')
-          result.push(redis.createClient(x))
-        }
-      }
-      return result
-    })()
-    return clientList
+    return configs.filter(Boolean).map((x) => {
+      const redisType = x.cluster
+        ? 'cluster'
+        : x.sentinels
+        ? 'sentinel'
+        : x.host
+        ? 'single'
+        : 'unknown'
+      logger.log({ redis: redisType }, 'creating redis client')
+      return redis.createClient(x)
+    })
   }
 }
diff --git a/services/real-time/app/js/RoomManager.js b/services/real-time/app/js/RoomManager.js
index 8dd34e9340..81827e5e9a 100644
--- a/services/real-time/app/js/RoomManager.js
+++ b/services/real-time/app/js/RoomManager.js
@@ -1,19 +1,6 @@
 /* eslint-disable
     camelcase,
-    no-unused-vars,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS102: Remove unnecessary code created because of implicit returns
- * DS103: Rewrite code to no longer use __guard__
- * DS205: Consider reworking code to avoid use of IIFEs
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let RoomManager
 const logger = require('logger-sharelatex')
 const metrics = require('metrics-sharelatex')
 const { EventEmitter } = require('events')
@@ -31,23 +18,17 @@ const RoomEvents = new EventEmitter() // emits {project,doc}-active and {project
 //
 // The pubsub side is handled by ChannelManager
 
-module.exports = RoomManager = {
+module.exports = {
   joinProject(client, project_id, callback) {
-    if (callback == null) {
-      callback = function () {}
-    }
-    return this.joinEntity(client, 'project', project_id, callback)
+    this.joinEntity(client, 'project', project_id, callback)
   },
 
   joinDoc(client, doc_id, callback) {
-    if (callback == null) {
-      callback = function () {}
-    }
-    return this.joinEntity(client, 'doc', doc_id, callback)
+    this.joinEntity(client, 'doc', doc_id, callback)
   },
 
   leaveDoc(client, doc_id) {
-    return this.leaveEntity(client, 'doc', doc_id)
+    this.leaveEntity(client, 'doc', doc_id)
   },
 
   leaveProjectAndDocs(client) {
@@ -58,18 +39,14 @@ module.exports = RoomManager = {
     // has not joined any rooms and do a final disconnection.
     const roomsToLeave = this._roomsClientIsIn(client)
     logger.log({ client: client.id, roomsToLeave }, 'client leaving project')
-    return (() => {
-      const result = []
-      for (const id of Array.from(roomsToLeave)) {
-        const entity = IdMap.get(id)
-        result.push(this.leaveEntity(client, entity, id))
-      }
-      return result
-    })()
+    for (const id of roomsToLeave) {
+      const entity = IdMap.get(id)
+      this.leaveEntity(client, entity, id)
+    }
   },
 
   emitOnCompletion(promiseList, eventName) {
-    return Promise.all(promiseList)
+    Promise.all(promiseList)
       .then(() => RoomEvents.emit(eventName))
       .catch((err) => RoomEvents.emit(eventName, err))
   },
@@ -92,19 +69,19 @@ module.exports = RoomManager = {
           { client: client.id, entity, id, beforeCount },
           'client joined new room and subscribed to channel'
         )
-        return callback(err)
+        callback(err)
       })
       RoomEvents.emit(`${entity}-active`, id)
       IdMap.set(id, entity)
       // keep track of the number of listeners
-      return metrics.gauge('room-listeners', RoomEvents.eventNames().length)
+      metrics.gauge('room-listeners', RoomEvents.eventNames().length)
     } else {
       logger.log(
         { client: client.id, entity, id, beforeCount },
         'client joined existing room'
       )
       client.join(id)
-      return callback()
+      callback()
     }
   },
 
@@ -128,7 +105,7 @@ module.exports = RoomManager = {
       'client left room'
     )
     // is the room now empty? if so, unsubscribe
-    if (entity == null) {
+    if (!entity) {
       logger.error({ entity: id }, 'unknown entity when leaving with id')
       return
     }
@@ -136,54 +113,48 @@ module.exports = RoomManager = {
       logger.log({ entity, id }, 'room is now empty')
       RoomEvents.emit(`${entity}-empty`, id)
       IdMap.delete(id)
-      return metrics.gauge('room-listeners', RoomEvents.eventNames().length)
+      metrics.gauge('room-listeners', RoomEvents.eventNames().length)
     }
   },
 
   // internal functions below, these access socket.io rooms data directly and
   // will need updating for socket.io v2
 
+  // The below code makes some assumptions that are always true for v0
+  // - we are using the base namespace '', so room names are '/<ENTITY>'
+  //   https://github.com/socketio/socket.io/blob/e4d61b1be65ac3313a85da111a46777aa8d4aae3/lib/manager.js#L62
+  //   https://github.com/socketio/socket.io/blob/e4d61b1be65ac3313a85da111a46777aa8d4aae3/lib/manager.js#L1018
+  // - client.namespace is a Namespace
+  //   https://github.com/socketio/socket.io/blob/e4d61b1be65ac3313a85da111a46777aa8d4aae3/lib/namespace.js#L204
+  //   https://github.com/socketio/socket.io/blob/e4d61b1be65ac3313a85da111a46777aa8d4aae3/lib/socket.js#L40
+  // - client.manager is a Manager
+  //   https://github.com/socketio/socket.io/blob/e4d61b1be65ac3313a85da111a46777aa8d4aae3/lib/namespace.js#L204
+  //   https://github.com/socketio/socket.io/blob/e4d61b1be65ac3313a85da111a46777aa8d4aae3/lib/socket.js#L41
+  // - a Manager has
+  //   - `.rooms={'NAMESPACE/ENTITY': []}` and
+  //   - `.roomClients={'CLIENT_ID': {'...': true}}`
+  //   https://github.com/socketio/socket.io/blob/e4d61b1be65ac3313a85da111a46777aa8d4aae3/lib/manager.js#L287-L288
+  //   https://github.com/socketio/socket.io/blob/e4d61b1be65ac3313a85da111a46777aa8d4aae3/lib/manager.js#L444-L455
+
   _clientsInRoom(client, room) {
-    const nsp = client.namespace.name
-    const name = nsp + '/' + room
-    return (
-      __guard__(
-        client.manager != null ? client.manager.rooms : undefined,
-        (x) => x[name]
-      ) || []
-    ).length
+    const clients = client.manager.rooms['/' + room] || []
+    return clients.length
   },
 
   _roomsClientIsIn(client) {
-    const roomList = (() => {
-      const result = []
-      for (const fullRoomPath in client.manager.roomClients != null
-        ? client.manager.roomClients[client.id]
-        : undefined) {
-        // strip socket.io prefix from room to get original id
-        if (fullRoomPath !== '') {
-          const [prefix, room] = Array.from(fullRoomPath.split('/', 2))
-          result.push(room)
-        }
-      }
-      return result
-    })()
-    return roomList
+    const rooms = client.manager.roomClients[client.id] || {}
+    return (
+      Object.keys(rooms)
+        // drop the namespace
+        .filter((room) => room !== '')
+        // room names are composed as '<NAMESPACE>/<ROOM>' and the default
+        //  namespace is empty (see comments above), just drop the '/'
+        .map((fullRoomPath) => fullRoomPath.slice(1))
+    )
   },
 
   _clientAlreadyInRoom(client, room) {
-    const nsp = client.namespace.name
-    const name = nsp + '/' + room
-    return __guard__(
-      client.manager.roomClients != null
-        ? client.manager.roomClients[client.id]
-        : undefined,
-      (x) => x[name]
-    )
+    const rooms = client.manager.roomClients[client.id] || {}
+    return !!rooms['/' + room]
   }
 }
-function __guard__(value, transform) {
-  return typeof value !== 'undefined' && value !== null
-    ? transform(value)
-    : undefined
-}
diff --git a/services/real-time/app/js/Router.js b/services/real-time/app/js/Router.js
index 0e19c46bc0..02c751c22f 100644
--- a/services/real-time/app/js/Router.js
+++ b/services/real-time/app/js/Router.js
@@ -1,19 +1,6 @@
 /* eslint-disable
     camelcase,
-    handle-callback-err,
-    standard/no-callback-literal,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS102: Remove unnecessary code created because of implicit returns
- * DS103: Rewrite code to no longer use __guard__
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let Router
 const metrics = require('metrics-sharelatex')
 const logger = require('logger-sharelatex')
 const settings = require('settings-sharelatex')
@@ -34,14 +21,10 @@ const httpAuth = basicAuth(function (user, pass) {
   return isValid
 })
 
+let Router
 module.exports = Router = {
   _handleError(callback, error, client, method, attrs) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
-    if (attrs == null) {
-      attrs = {}
-    }
+    attrs = attrs || {}
     for (const key of ['project_id', 'doc_id', 'user_id']) {
       attrs[key] = client.ol_context[key]
     }
@@ -49,15 +32,15 @@ module.exports = Router = {
     attrs.err = error
     if (error.name === 'CodedError') {
       logger.warn(attrs, error.message, { code: error.code })
-      return callback({ message: error.message, code: error.code })
-    }
-    if (error.message === 'unexpected arguments') {
+      const serializedError = { message: error.message, code: error.code }
+      callback(serializedError)
+    } else if (error.message === 'unexpected arguments') {
       // the payload might be very large, put it on level info
       logger.log(attrs, 'unexpected arguments')
       metrics.inc('unexpected-arguments', 1, { status: method })
-      return callback({ message: error.message })
-    }
-    if (
+      const serializedError = { message: error.message }
+      callback(serializedError)
+    } else if (
       [
         'not authorized',
         'doc updater could not load requested ops',
@@ -65,11 +48,15 @@ module.exports = Router = {
       ].includes(error.message)
     ) {
       logger.warn(attrs, error.message)
-      return callback({ message: error.message })
+      const serializedError = { message: error.message }
+      callback(serializedError)
     } else {
       logger.error(attrs, `server side error in ${method}`)
       // Don't return raw error to prevent leaking server side info
-      return callback({ message: 'Something went wrong in real-time service' })
+      const serializedError = {
+        message: 'Something went wrong in real-time service'
+      }
+      callback(serializedError)
     }
   },
 
@@ -80,7 +67,7 @@ module.exports = Router = {
       callback = function () {}
     }
     const attrs = { arguments: args }
-    return Router._handleError(callback, error, client, method, attrs)
+    Router._handleError(callback, error, client, method, attrs)
   },
 
   configure(app, io, session) {
@@ -102,18 +89,17 @@ module.exports = Router = {
       HttpApiController.disconnectClient
     )
 
-    return session.on('connection', function (error, client, session) {
+    session.on('connection', function (error, client, session) {
       // init client context, we may access it in Router._handleError before
       //  setting any values
-      let user
       client.ol_context = {}
 
-      if (client != null) {
+      if (client) {
         client.on('error', function (err) {
           logger.err({ clientErr: err }, 'socket.io client error')
           if (client.connected) {
             client.emit('reconnectGracefully')
-            return client.disconnect()
+            client.disconnect()
           }
         })
       }
@@ -125,13 +111,12 @@ module.exports = Router = {
       }
 
       if (
-        client != null &&
-        __guard__(error != null ? error.message : undefined, (x) =>
-          x.match(/could not look up session by key/)
-        )
+        client &&
+        error &&
+        error.message.match(/could not look up session by key/)
       ) {
         logger.warn(
-          { err: error, client: client != null, session: session != null },
+          { err: error, client: !!client, session: !!session },
           'invalid session'
         )
         // tell the client to reauthenticate if it has an invalid session key
@@ -140,15 +125,15 @@ module.exports = Router = {
         return
       }
 
-      if (error != null) {
+      if (error) {
         logger.err(
-          { err: error, client: client != null, session: session != null },
+          { err: error, client: !!client, session: !!session },
           'error when client connected'
         )
-        if (client != null) {
+        if (client) {
           client.emit('connectionRejected', { message: 'error' })
         }
-        if (client != null) {
+        if (client) {
           client.disconnect()
         }
         return
@@ -159,30 +144,21 @@ module.exports = Router = {
       client.emit('connectionAccepted', null, client.publicId)
 
       metrics.inc('socket-io.connection')
-      metrics.gauge(
-        'socket-io.clients',
-        __guard__(io.sockets.clients(), (x1) => x1.length)
-      )
+      metrics.gauge('socket-io.clients', io.sockets.clients().length)
 
       logger.log({ session, client_id: client.id }, 'client connected')
 
-      if (
-        __guard__(
-          session != null ? session.passport : undefined,
-          (x2) => x2.user
-        ) != null
-      ) {
+      let user
+      if (session && session.passport && session.passport.user) {
         ;({ user } = session.passport)
-      } else if ((session != null ? session.user : undefined) != null) {
+      } else if (session && session.user) {
         ;({ user } = session)
       } else {
         user = { _id: 'anonymous-user' }
       }
 
       client.on('joinProject', function (data, callback) {
-        if (data == null) {
-          data = {}
-        }
+        data = data || {}
         if (typeof callback !== 'function') {
           return Router._handleInvalidArguments(
             client,
@@ -194,18 +170,18 @@ module.exports = Router = {
         if (data.anonymousAccessToken) {
           user.anonymousAccessToken = data.anonymousAccessToken
         }
-        return WebsocketController.joinProject(
+        WebsocketController.joinProject(
           client,
           user,
           data.project_id,
           function (err, ...args) {
-            if (err != null) {
-              return Router._handleError(callback, err, client, 'joinProject', {
+            if (err) {
+              Router._handleError(callback, err, client, 'joinProject', {
                 project_id: data.project_id,
-                user_id: user != null ? user.id : undefined
+                user_id: user._id
               })
             } else {
-              return callback(null, ...Array.from(args))
+              callback(null, ...args)
             }
           }
         )
@@ -213,19 +189,11 @@ module.exports = Router = {
 
       client.on('disconnect', function () {
         metrics.inc('socket-io.disconnect')
-        metrics.gauge(
-          'socket-io.clients',
-          __guard__(io.sockets.clients(), (x3) => x3.length) - 1
-        )
+        metrics.gauge('socket-io.clients', io.sockets.clients().length)
 
-        return WebsocketController.leaveProject(io, client, function (err) {
-          if (err != null) {
-            return Router._handleError(
-              function () {},
-              err,
-              client,
-              'leaveProject'
-            )
+        WebsocketController.leaveProject(io, client, function (err) {
+          if (err) {
+            Router._handleError(function () {}, err, client, 'leaveProject')
           }
         })
       })
@@ -263,19 +231,19 @@ module.exports = Router = {
           return Router._handleInvalidArguments(client, 'joinDoc', arguments)
         }
 
-        return WebsocketController.joinDoc(
+        WebsocketController.joinDoc(
           client,
           doc_id,
           fromVersion,
           options,
           function (err, ...args) {
-            if (err != null) {
-              return Router._handleError(callback, err, client, 'joinDoc', {
+            if (err) {
+              Router._handleError(callback, err, client, 'joinDoc', {
                 doc_id,
                 fromVersion
               })
             } else {
-              return callback(null, ...Array.from(args))
+              callback(null, ...args)
             }
           }
         )
@@ -286,22 +254,16 @@ module.exports = Router = {
           return Router._handleInvalidArguments(client, 'leaveDoc', arguments)
         }
 
-        return WebsocketController.leaveDoc(client, doc_id, function (
-          err,
-          ...args
-        ) {
-          if (err != null) {
-            return Router._handleError(callback, err, client, 'leaveDoc')
+        WebsocketController.leaveDoc(client, doc_id, function (err, ...args) {
+          if (err) {
+            Router._handleError(callback, err, client, 'leaveDoc')
           } else {
-            return callback(null, ...Array.from(args))
+            callback(null, ...args)
           }
         })
       })
 
       client.on('clientTracking.getConnectedUsers', function (callback) {
-        if (callback == null) {
-          callback = function (error, users) {}
-        }
         if (typeof callback !== 'function') {
           return Router._handleInvalidArguments(
             client,
@@ -310,19 +272,16 @@ module.exports = Router = {
           )
         }
 
-        return WebsocketController.getConnectedUsers(client, function (
-          err,
-          users
-        ) {
-          if (err != null) {
-            return Router._handleError(
+        WebsocketController.getConnectedUsers(client, function (err, users) {
+          if (err) {
+            Router._handleError(
               callback,
               err,
               client,
               'clientTracking.getConnectedUsers'
             )
           } else {
-            return callback(null, users)
+            callback(null, users)
           }
         })
       })
@@ -331,8 +290,8 @@ module.exports = Router = {
         cursorData,
         callback
       ) {
-        if (callback == null) {
-          callback = function (error) {}
+        if (!callback) {
+          callback = function () {}
         }
         if (typeof callback !== 'function') {
           return Router._handleInvalidArguments(
@@ -342,28 +301,23 @@ module.exports = Router = {
           )
         }
 
-        return WebsocketController.updateClientPosition(
-          client,
-          cursorData,
-          function (err) {
-            if (err != null) {
-              return Router._handleError(
-                callback,
-                err,
-                client,
-                'clientTracking.updatePosition'
-              )
-            } else {
-              return callback()
-            }
+        WebsocketController.updateClientPosition(client, cursorData, function (
+          err
+        ) {
+          if (err) {
+            Router._handleError(
+              callback,
+              err,
+              client,
+              'clientTracking.updatePosition'
+            )
+          } else {
+            callback()
           }
-        )
+        })
       })
 
-      return client.on('applyOtUpdate', function (doc_id, update, callback) {
-        if (callback == null) {
-          callback = function (error) {}
-        }
+      client.on('applyOtUpdate', function (doc_id, update, callback) {
         if (typeof callback !== 'function') {
           return Router._handleInvalidArguments(
             client,
@@ -372,31 +326,19 @@ module.exports = Router = {
           )
         }
 
-        return WebsocketController.applyOtUpdate(
-          client,
-          doc_id,
-          update,
-          function (err) {
-            if (err != null) {
-              return Router._handleError(
-                callback,
-                err,
-                client,
-                'applyOtUpdate',
-                { doc_id, update }
-              )
-            } else {
-              return callback()
-            }
+        WebsocketController.applyOtUpdate(client, doc_id, update, function (
+          err
+        ) {
+          if (err) {
+            Router._handleError(callback, err, client, 'applyOtUpdate', {
+              doc_id,
+              update
+            })
+          } else {
+            callback()
           }
-        )
+        })
       })
     })
   }
 }
-
-function __guard__(value, transform) {
-  return typeof value !== 'undefined' && value !== null
-    ? transform(value)
-    : undefined
-}
diff --git a/services/real-time/app/js/SafeJsonParse.js b/services/real-time/app/js/SafeJsonParse.js
index 6e2e287853..982fd9d424 100644
--- a/services/real-time/app/js/SafeJsonParse.js
+++ b/services/real-time/app/js/SafeJsonParse.js
@@ -1,23 +1,8 @@
-/* eslint-disable
-    handle-callback-err,
-*/
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
 const Settings = require('settings-sharelatex')
 const logger = require('logger-sharelatex')
 
 module.exports = {
   parse(data, callback) {
-    let parsed
-    if (callback == null) {
-      callback = function (error, parsed) {}
-    }
     if (data.length > Settings.maxUpdateSize) {
       logger.error(
         { head: data.slice(0, 1024), length: data.length },
@@ -25,11 +10,12 @@ module.exports = {
       )
       return callback(new Error('data too large to parse'))
     }
+    let parsed
     try {
       parsed = JSON.parse(data)
     } catch (e) {
       return callback(e)
     }
-    return callback(null, parsed)
+    callback(null, parsed)
   }
 }
diff --git a/services/real-time/app/js/SessionSockets.js b/services/real-time/app/js/SessionSockets.js
index b01920dfa7..4ade959829 100644
--- a/services/real-time/app/js/SessionSockets.js
+++ b/services/real-time/app/js/SessionSockets.js
@@ -1,34 +1,28 @@
-// TODO: This file was created by bulk-decaffeinate.
-// Sanity-check the conversion and remove this comment.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
 const { EventEmitter } = require('events')
 
 module.exports = function (io, sessionStore, cookieParser, cookieName) {
   const missingSessionError = new Error('could not look up session by key')
 
   const sessionSockets = new EventEmitter()
-  const next = (error, socket, session) =>
+  function next(error, socket, session) {
     sessionSockets.emit('connection', error, socket, session)
+  }
 
   io.on('connection', function (socket) {
     const req = socket.handshake
-    return cookieParser(req, {}, function () {
+    cookieParser(req, {}, function () {
       const sessionId = req.signedCookies && req.signedCookies[cookieName]
       if (!sessionId) {
         return next(missingSessionError, socket)
       }
-      return sessionStore.get(sessionId, function (error, session) {
+      sessionStore.get(sessionId, function (error, session) {
         if (error) {
           return next(error, socket)
         }
         if (!session) {
           return next(missingSessionError, socket)
         }
-        return next(null, socket, session)
+        next(null, socket, session)
       })
     })
   })
diff --git a/services/real-time/app/js/WebApiManager.js b/services/real-time/app/js/WebApiManager.js
index 266135333a..62020a98ab 100644
--- a/services/real-time/app/js/WebApiManager.js
+++ b/services/real-time/app/js/WebApiManager.js
@@ -1,35 +1,21 @@
 /* eslint-disable
     camelcase,
-    handle-callback-err,
-    no-unused-vars,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS102: Remove unnecessary code created because of implicit returns
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let WebApiManager
 const request = require('request')
 const settings = require('settings-sharelatex')
 const logger = require('logger-sharelatex')
 const { CodedError } = require('./Errors')
 
-module.exports = WebApiManager = {
+module.exports = {
   joinProject(project_id, user, callback) {
-    if (callback == null) {
-      callback = function (error, project, privilegeLevel, isRestrictedUser) {}
-    }
     const user_id = user._id
     logger.log({ project_id, user_id }, 'sending join project request to web')
     const url = `${settings.apis.web.url}/project/${project_id}/join`
     const headers = {}
-    if (user.anonymousAccessToken != null) {
+    if (user.anonymousAccessToken) {
       headers['x-sl-anonymous-access-token'] = user.anonymousAccessToken
     }
-    return request.post(
+    request.post(
       {
         url,
         qs: { user_id },
@@ -43,15 +29,12 @@ module.exports = WebApiManager = {
         headers
       },
       function (error, response, data) {
-        let err
-        if (error != null) {
+        if (error) {
           return callback(error)
         }
+        let err
         if (response.statusCode >= 200 && response.statusCode < 300) {
-          if (
-            data == null ||
-            (data != null ? data.project : undefined) == null
-          ) {
+          if (!(data && data.project)) {
             err = new Error('no data returned from joinProject request')
             logger.error(
               { err, project_id, user_id },
@@ -59,7 +42,7 @@ module.exports = WebApiManager = {
             )
             return callback(err)
           }
-          return callback(
+          callback(
             null,
             data.project,
             data.privilegeLevel,
@@ -67,7 +50,7 @@ module.exports = WebApiManager = {
           )
         } else if (response.statusCode === 429) {
           logger.log(project_id, user_id, 'rate-limit hit when joining project')
-          return callback(
+          callback(
             new CodedError(
               'rate-limit hit when joining project',
               'TooManyRequests'
@@ -78,7 +61,7 @@ module.exports = WebApiManager = {
             `non-success status code from web: ${response.statusCode}`
           )
           logger.error({ err, project_id, user_id }, 'error accessing web api')
-          return callback(err)
+          callback(err)
         }
       }
     )
diff --git a/services/real-time/app/js/WebsocketController.js b/services/real-time/app/js/WebsocketController.js
index 451c514336..239372eea9 100644
--- a/services/real-time/app/js/WebsocketController.js
+++ b/services/real-time/app/js/WebsocketController.js
@@ -1,22 +1,8 @@
 /* eslint-disable
     camelcase,
-    handle-callback-err,
-    no-unused-vars,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS102: Remove unnecessary code created because of implicit returns
- * DS103: Rewrite code to no longer use __guard__
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let WebsocketController
 const logger = require('logger-sharelatex')
 const metrics = require('metrics-sharelatex')
-const settings = require('settings-sharelatex')
 const WebApiManager = require('./WebApiManager')
 const AuthorizationManager = require('./AuthorizationManager')
 const DocumentUpdaterManager = require('./DocumentUpdaterManager')
@@ -24,6 +10,7 @@ const ConnectedUsersManager = require('./ConnectedUsersManager')
 const WebsocketLoadBalancer = require('./WebsocketLoadBalancer')
 const RoomManager = require('./RoomManager')
 
+let WebsocketController
 module.exports = WebsocketController = {
   // If the protocol version changes when the client reconnects,
   // it will force a full refresh of the page. Useful for non-backwards
@@ -31,9 +18,6 @@ module.exports = WebsocketController = {
   PROTOCOL_VERSION: 2,
 
   joinProject(client, user, project_id, callback) {
-    if (callback == null) {
-      callback = function (error, project, privilegeLevel, protocolVersion) {}
-    }
     if (client.disconnected) {
       metrics.inc('editor.join-project.disconnected', 1, {
         status: 'immediately'
@@ -41,19 +25,19 @@ module.exports = WebsocketController = {
       return callback()
     }
 
-    const user_id = user != null ? user._id : undefined
+    const user_id = user._id
     logger.log(
       { user_id, project_id, client_id: client.id },
       'user joining project'
     )
     metrics.inc('editor.join-project')
-    return WebApiManager.joinProject(project_id, user, function (
+    WebApiManager.joinProject(project_id, user, function (
       error,
       project,
       privilegeLevel,
       isRestrictedUser
     ) {
-      if (error != null) {
+      if (error) {
         return callback(error)
       }
       if (client.disconnected) {
@@ -63,7 +47,7 @@ module.exports = WebsocketController = {
         return callback()
       }
 
-      if (!privilegeLevel || privilegeLevel === '') {
+      if (!privilegeLevel) {
         const err = new Error('not authorized')
         logger.warn(
           { err, project_id, user_id, client_id: client.id },
@@ -76,16 +60,13 @@ module.exports = WebsocketController = {
       client.ol_context.privilege_level = privilegeLevel
       client.ol_context.user_id = user_id
       client.ol_context.project_id = project_id
-      client.ol_context.owner_id = __guard__(
-        project != null ? project.owner : undefined,
-        (x) => x._id
-      )
-      client.ol_context.first_name = user != null ? user.first_name : undefined
-      client.ol_context.last_name = user != null ? user.last_name : undefined
-      client.ol_context.email = user != null ? user.email : undefined
+      client.ol_context.owner_id = project.owner && project.owner._id
+      client.ol_context.first_name = user.first_name
+      client.ol_context.last_name = user.last_name
+      client.ol_context.email = user.email
       client.ol_context.connected_time = new Date()
-      client.ol_context.signup_date = user != null ? user.signUpDate : undefined
-      client.ol_context.login_count = user != null ? user.loginCount : undefined
+      client.ol_context.signup_date = user.signUpDate
+      client.ol_context.login_count = user.loginCount
       client.ol_context.is_restricted_user = !!isRestrictedUser
 
       RoomManager.joinProject(client, project_id, function (err) {
@@ -96,7 +77,7 @@ module.exports = WebsocketController = {
           { user_id, project_id, client_id: client.id },
           'user joined project'
         )
-        return callback(
+        callback(
           null,
           project,
           privilegeLevel,
@@ -105,7 +86,7 @@ module.exports = WebsocketController = {
       })
 
       // No need to block for setting the user as connected in the cursor tracking
-      return ConnectedUsersManager.updateUserPosition(
+      ConnectedUsersManager.updateUserPosition(
         project_id,
         client.publicId,
         user,
@@ -120,9 +101,6 @@ module.exports = WebsocketController = {
   // is determined by FLUSH_IF_EMPTY_DELAY.
   FLUSH_IF_EMPTY_DELAY: 500, // ms
   leaveProject(io, client, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
     const { project_id, user_id } = client.ol_context
     if (!project_id) {
       return callback()
@@ -144,8 +122,8 @@ module.exports = WebsocketController = {
       project_id,
       client.publicId,
       function (err) {
-        if (err != null) {
-          return logger.error(
+        if (err) {
+          logger.error(
             { err, project_id, user_id, client_id: client.id },
             'error marking client as disconnected'
           )
@@ -154,15 +132,15 @@ module.exports = WebsocketController = {
     )
 
     RoomManager.leaveProjectAndDocs(client)
-    return setTimeout(function () {
+    setTimeout(function () {
       const remainingClients = io.sockets.clients(project_id)
       if (remainingClients.length === 0) {
         // Flush project in the background
         DocumentUpdaterManager.flushProjectToMongoAndDelete(
           project_id,
           function (err) {
-            if (err != null) {
-              return logger.error(
+            if (err) {
+              logger.error(
                 { err, project_id, user_id, client_id: client.id },
                 'error flushing to doc updater after leaving project'
               )
@@ -170,17 +148,11 @@ module.exports = WebsocketController = {
           }
         )
       }
-      return callback()
+      callback()
     }, WebsocketController.FLUSH_IF_EMPTY_DELAY)
   },
 
   joinDoc(client, doc_id, fromVersion, options, callback) {
-    if (fromVersion == null) {
-      fromVersion = -1
-    }
-    if (callback == null) {
-      callback = function (error, doclines, version, ops, ranges) {}
-    }
     if (client.disconnected) {
       metrics.inc('editor.join-doc.disconnected', 1, { status: 'immediately' })
       return callback()
@@ -188,7 +160,7 @@ module.exports = WebsocketController = {
 
     metrics.inc('editor.join-doc')
     const { project_id, user_id, is_restricted_user } = client.ol_context
-    if (project_id == null) {
+    if (!project_id) {
       return callback(new Error('no project_id found on client'))
     }
     logger.log(
@@ -196,16 +168,14 @@ module.exports = WebsocketController = {
       'client joining doc'
     )
 
-    return AuthorizationManager.assertClientCanViewProject(client, function (
-      error
-    ) {
-      if (error != null) {
+    AuthorizationManager.assertClientCanViewProject(client, function (error) {
+      if (error) {
         return callback(error)
       }
       // ensure the per-doc applied-ops channel is subscribed before sending the
       // doc to the client, so that no events are missed.
-      return RoomManager.joinDoc(client, doc_id, function (error) {
-        if (error != null) {
+      RoomManager.joinDoc(client, doc_id, function (error) {
+        if (error) {
           return callback(error)
         }
         if (client.disconnected) {
@@ -216,13 +186,12 @@ module.exports = WebsocketController = {
           return callback()
         }
 
-        return DocumentUpdaterManager.getDocument(
+        DocumentUpdaterManager.getDocument(
           project_id,
           doc_id,
           fromVersion,
           function (error, lines, version, ranges, ops) {
-            let err
-            if (error != null) {
+            if (error) {
               return callback(error)
             }
             if (client.disconnected) {
@@ -233,10 +202,7 @@ module.exports = WebsocketController = {
               return callback()
             }
 
-            if (
-              is_restricted_user &&
-              (ranges != null ? ranges.comments : undefined) != null
-            ) {
+            if (is_restricted_user && ranges && ranges.comments) {
               ranges.comments = []
             }
 
@@ -245,11 +211,10 @@ module.exports = WebsocketController = {
             const encodeForWebsockets = (text) =>
               unescape(encodeURIComponent(text))
             const escapedLines = []
-            for (let line of Array.from(lines)) {
+            for (let line of lines) {
               try {
                 line = encodeForWebsockets(line)
-              } catch (error1) {
-                err = error1
+              } catch (err) {
                 logger.err(
                   {
                     err,
@@ -267,25 +232,20 @@ module.exports = WebsocketController = {
             }
             if (options.encodeRanges) {
               try {
-                for (const comment of Array.from(
-                  (ranges != null ? ranges.comments : undefined) || []
-                )) {
-                  if (comment.op.c != null) {
+                for (const comment of (ranges && ranges.comments) || []) {
+                  if (comment.op.c) {
                     comment.op.c = encodeForWebsockets(comment.op.c)
                   }
                 }
-                for (const change of Array.from(
-                  (ranges != null ? ranges.changes : undefined) || []
-                )) {
-                  if (change.op.i != null) {
+                for (const change of (ranges && ranges.changes) || []) {
+                  if (change.op.i) {
                     change.op.i = encodeForWebsockets(change.op.i)
                   }
-                  if (change.op.d != null) {
+                  if (change.op.d) {
                     change.op.d = encodeForWebsockets(change.op.d)
                   }
                 }
-              } catch (error2) {
-                err = error2
+              } catch (err) {
                 logger.err(
                   {
                     err,
@@ -301,7 +261,7 @@ module.exports = WebsocketController = {
               }
             }
 
-            AuthorizationManager.addAccessToDoc(client, doc_id)
+            AuthorizationManager.addAccessToDoc(client, doc_id, () => {})
             logger.log(
               {
                 user_id,
@@ -312,7 +272,7 @@ module.exports = WebsocketController = {
               },
               'client joined doc'
             )
-            return callback(null, escapedLines, version, ops, ranges)
+            callback(null, escapedLines, version, ops, ranges)
           }
         )
       })
@@ -321,9 +281,6 @@ module.exports = WebsocketController = {
 
   leaveDoc(client, doc_id, callback) {
     // client may have disconnected, but we have to cleanup internal state.
-    if (callback == null) {
-      callback = function (error) {}
-    }
     metrics.inc('editor.leave-doc')
     const { project_id, user_id } = client.ol_context
     logger.log(
@@ -335,12 +292,9 @@ module.exports = WebsocketController = {
     // the connection is per-project, we continue to allow access
     // after the initial joinDoc since we know they are already authorised.
     // # AuthorizationManager.removeAccessToDoc client, doc_id
-    return callback()
+    callback()
   },
   updateClientPosition(client, cursorData, callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
     if (client.disconnected) {
       // do not create a ghost entry in redis
       return callback()
@@ -359,11 +313,11 @@ module.exports = WebsocketController = {
       'updating client position'
     )
 
-    return AuthorizationManager.assertClientCanViewProjectAndDoc(
+    AuthorizationManager.assertClientCanViewProjectAndDoc(
       client,
       cursorData.doc_id,
       function (error) {
-        if (error != null) {
+        if (error) {
           logger.warn(
             { err: error, client_id: client.id, project_id, user_id },
             "silently ignoring unauthorized updateClientPosition. Client likely hasn't called joinProject yet."
@@ -371,10 +325,10 @@ module.exports = WebsocketController = {
           return callback()
         }
         cursorData.id = client.publicId
-        if (user_id != null) {
+        if (user_id) {
           cursorData.user_id = user_id
         }
-        if (email != null) {
+        if (email) {
           cursorData.email = email
         }
         // Don't store anonymous users in redis to avoid influx
@@ -404,7 +358,7 @@ module.exports = WebsocketController = {
             callback
           )
         }
-        return WebsocketLoadBalancer.emitToRoom(
+        WebsocketLoadBalancer.emitToRoom(
           project_id,
           'clientTracking.clientUpdated',
           cursorData
@@ -415,9 +369,6 @@ module.exports = WebsocketController = {
 
   CLIENT_REFRESH_DELAY: 1000,
   getConnectedUsers(client, callback) {
-    if (callback == null) {
-      callback = function (error, users) {}
-    }
     if (client.disconnected) {
       // they are not interested anymore, skip the redis lookups
       return callback()
@@ -428,34 +379,32 @@ module.exports = WebsocketController = {
     if (is_restricted_user) {
       return callback(null, [])
     }
-    if (project_id == null) {
+    if (!project_id) {
       return callback(new Error('no project_id found on client'))
     }
     logger.log(
       { user_id, project_id, client_id: client.id },
       'getting connected users'
     )
-    return AuthorizationManager.assertClientCanViewProject(client, function (
-      error
-    ) {
-      if (error != null) {
+    AuthorizationManager.assertClientCanViewProject(client, function (error) {
+      if (error) {
         return callback(error)
       }
       WebsocketLoadBalancer.emitToRoom(project_id, 'clientTracking.refresh')
-      return setTimeout(
+      setTimeout(
         () =>
           ConnectedUsersManager.getConnectedUsers(project_id, function (
             error,
             users
           ) {
-            if (error != null) {
+            if (error) {
               return callback(error)
             }
-            callback(null, users)
-            return logger.log(
+            logger.log(
               { user_id, project_id, client_id: client.id },
               'got connected users'
             )
+            callback(null, users)
           }),
         WebsocketController.CLIENT_REFRESH_DELAY
       )
@@ -464,20 +413,17 @@ module.exports = WebsocketController = {
 
   applyOtUpdate(client, doc_id, update, callback) {
     // client may have disconnected, but we can submit their update to doc-updater anyways.
-    if (callback == null) {
-      callback = function (error) {}
-    }
     const { user_id, project_id } = client.ol_context
-    if (project_id == null) {
+    if (!project_id) {
       return callback(new Error('no project_id found on client'))
     }
 
-    return WebsocketController._assertClientCanApplyUpdate(
+    WebsocketController._assertClientCanApplyUpdate(
       client,
       doc_id,
       update,
       function (error) {
-        if (error != null) {
+        if (error) {
           logger.warn(
             { err: error, doc_id, client_id: client.id, version: update.v },
             'client is not authorized to make update'
@@ -508,15 +454,12 @@ module.exports = WebsocketController = {
           'sending update to doc updater'
         )
 
-        return DocumentUpdaterManager.queueChange(
+        DocumentUpdaterManager.queueChange(
           project_id,
           doc_id,
           update,
           function (error) {
-            if (
-              (error != null ? error.message : undefined) ===
-              'update is too large'
-            ) {
+            if ((error && error.message) === 'update is too large') {
               metrics.inc('update_too_large')
               const { updateSize } = error
               logger.warn(
@@ -541,12 +484,12 @@ module.exports = WebsocketController = {
                   })
                 }
                 client.emit('otUpdateError', message.error, message)
-                return client.disconnect()
+                client.disconnect()
               }, 100)
               return
             }
 
-            if (error != null) {
+            if (error) {
               logger.error(
                 {
                   err: error,
@@ -559,7 +502,7 @@ module.exports = WebsocketController = {
               )
               client.disconnect()
             }
-            return callback(error)
+            callback(error)
           }
         )
       }
@@ -567,43 +510,37 @@ module.exports = WebsocketController = {
   },
 
   _assertClientCanApplyUpdate(client, doc_id, update, callback) {
-    return AuthorizationManager.assertClientCanEditProjectAndDoc(
+    AuthorizationManager.assertClientCanEditProjectAndDoc(
       client,
       doc_id,
       function (error) {
-        if (error != null) {
-          if (
-            error.message === 'not authorized' &&
-            WebsocketController._isCommentUpdate(update)
-          ) {
-            // This might be a comment op, which we only need read-only priveleges for
-            return AuthorizationManager.assertClientCanViewProjectAndDoc(
-              client,
-              doc_id,
-              callback
-            )
-          } else {
-            return callback(error)
-          }
-        } else {
-          return callback(null)
+        if (
+          error &&
+          error.message === 'not authorized' &&
+          WebsocketController._isCommentUpdate(update)
+        ) {
+          // This might be a comment op, which we only need read-only priveleges for
+          AuthorizationManager.assertClientCanViewProjectAndDoc(
+            client,
+            doc_id,
+            callback
+          )
+          return
         }
+        callback(error)
       }
     )
   },
 
   _isCommentUpdate(update) {
-    for (const op of Array.from(update.op)) {
-      if (op.c == null) {
+    if (!(update && update.op instanceof Array)) {
+      return false
+    }
+    for (const op of update.op) {
+      if (!op.c) {
         return false
       }
     }
     return true
   }
 }
-
-function __guard__(value, transform) {
-  return typeof value !== 'undefined' && value !== null
-    ? transform(value)
-    : undefined
-}
diff --git a/services/real-time/app/js/WebsocketLoadBalancer.js b/services/real-time/app/js/WebsocketLoadBalancer.js
index 2719921f10..ee6ba4d335 100644
--- a/services/real-time/app/js/WebsocketLoadBalancer.js
+++ b/services/real-time/app/js/WebsocketLoadBalancer.js
@@ -1,17 +1,6 @@
 /* eslint-disable
     camelcase,
 */
-// TODO: This file was created by bulk-decaffeinate.
-// Fix any style issues and re-enable lint.
-/*
- * decaffeinate suggestions:
- * DS101: Remove unnecessary use of Array.from
- * DS102: Remove unnecessary code created because of implicit returns
- * DS205: Consider reworking code to avoid use of IIFEs
- * DS207: Consider shorter variations of null checks
- * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
- */
-let WebsocketLoadBalancer
 const Settings = require('settings-sharelatex')
 const logger = require('logger-sharelatex')
 const RedisClientManager = require('./RedisClientManager')
@@ -33,12 +22,13 @@ const RESTRICTED_USER_MESSAGE_TYPE_PASS_LIST = [
   'removeEntity'
 ]
 
+let WebsocketLoadBalancer
 module.exports = WebsocketLoadBalancer = {
   rclientPubList: RedisClientManager.createClientList(Settings.redis.pubsub),
   rclientSubList: RedisClientManager.createClientList(Settings.redis.pubsub),
 
   emitToRoom(room_id, message, ...payload) {
-    if (room_id == null) {
+    if (!room_id) {
       logger.warn(
         { message, payload },
         'no room_id provided, ignoring emitToRoom'
@@ -55,99 +45,78 @@ module.exports = WebsocketLoadBalancer = {
       'emitting to room'
     )
 
-    return Array.from(this.rclientPubList).map((rclientPub) =>
+    this.rclientPubList.map((rclientPub) =>
       ChannelManager.publish(rclientPub, 'editor-events', room_id, data)
     )
   },
 
   emitToAll(message, ...payload) {
-    return this.emitToRoom('all', message, ...Array.from(payload))
+    this.emitToRoom('all', message, ...payload)
   },
 
   listenForEditorEvents(io) {
-    logger.log(
-      { rclients: this.rclientPubList.length },
-      'publishing editor events'
-    )
     logger.log(
       { rclients: this.rclientSubList.length },
       'listening for editor events'
     )
-    for (const rclientSub of Array.from(this.rclientSubList)) {
+    for (const rclientSub of this.rclientSubList) {
       rclientSub.subscribe('editor-events')
       rclientSub.on('message', function (channel, message) {
         if (Settings.debugEvents > 0) {
           EventLogger.debugEvent(channel, message)
         }
-        return WebsocketLoadBalancer._processEditorEvent(io, channel, message)
+        WebsocketLoadBalancer._processEditorEvent(io, channel, message)
       })
     }
-    return this.handleRoomUpdates(this.rclientSubList)
+    this.handleRoomUpdates(this.rclientSubList)
   },
 
   handleRoomUpdates(rclientSubList) {
     const roomEvents = RoomManager.eventSource()
     roomEvents.on('project-active', function (project_id) {
-      const subscribePromises = Array.from(rclientSubList).map((rclient) =>
+      const subscribePromises = rclientSubList.map((rclient) =>
         ChannelManager.subscribe(rclient, 'editor-events', project_id)
       )
-      return RoomManager.emitOnCompletion(
+      RoomManager.emitOnCompletion(
         subscribePromises,
         `project-subscribed-${project_id}`
       )
     })
-    return roomEvents.on('project-empty', (project_id) =>
-      Array.from(rclientSubList).map((rclient) =>
+    roomEvents.on('project-empty', (project_id) =>
+      rclientSubList.map((rclient) =>
         ChannelManager.unsubscribe(rclient, 'editor-events', project_id)
       )
     )
   },
 
   _processEditorEvent(io, channel, message) {
-    return SafeJsonParse.parse(message, function (error, message) {
-      let clientList
-      let client
-      if (error != null) {
+    SafeJsonParse.parse(message, function (error, message) {
+      if (error) {
         logger.error({ err: error, channel }, 'error parsing JSON')
         return
       }
       if (message.room_id === 'all') {
-        return io.sockets.emit(message.message, ...Array.from(message.payload))
+        io.sockets.emit(message.message, ...message.payload)
       } else if (
         message.message === 'clientTracking.refresh' &&
-        message.room_id != null
+        message.room_id
       ) {
-        clientList = io.sockets.clients(message.room_id)
+        const clientList = io.sockets.clients(message.room_id)
         logger.log(
           {
             channel,
             message: message.message,
             room_id: message.room_id,
             message_id: message._id,
-            socketIoClients: (() => {
-              const result = []
-              for (client of Array.from(clientList)) {
-                result.push(client.id)
-              }
-              return result
-            })()
+            socketIoClients: clientList.map((client) => client.id)
           },
           'refreshing client list'
         )
-        return (() => {
-          const result1 = []
-          for (client of Array.from(clientList)) {
-            result1.push(
-              ConnectedUsersManager.refreshClient(
-                message.room_id,
-                client.publicId
-              )
-            )
-          }
-          return result1
-        })()
-      } else if (message.room_id != null) {
-        if (message._id != null && Settings.checkEventOrder) {
+        for (const client of clientList) {
+          ConnectedUsersManager.refreshClient(message.room_id, client.publicId)
+        }
+      } else if (message.room_id) {
+        if (message._id && Settings.checkEventOrder) {
           const status = EventLogger.checkEventOrder(
             'editor-events',
             message._id,
@@ -158,12 +127,12 @@ module.exports = WebsocketLoadBalancer = {
           }
         }
 
-        const is_restricted_message = !Array.from(
-          RESTRICTED_USER_MESSAGE_TYPE_PASS_LIST
-        ).includes(message.message)
+        const is_restricted_message = !RESTRICTED_USER_MESSAGE_TYPE_PASS_LIST.includes(
+          message.message
+        )
 
         // send messages only to unique clients (due to duplicate entries in io.sockets.clients)
-        clientList = io.sockets
+        const clientList = io.sockets
           .clients(message.room_id)
           .filter(
             (client) =>
@@ -180,37 +149,23 @@ module.exports = WebsocketLoadBalancer = {
             message: message.message,
             room_id: message.room_id,
             message_id: message._id,
-            socketIoClients: (() => {
-              const result2 = []
-              for (client of Array.from(clientList)) {
-                result2.push(client.id)
-              }
-              return result2
-            })()
+            socketIoClients: clientList.map((client) => client.id)
           },
           'distributing event to clients'
         )
-        const seen = {}
-        return (() => {
-          const result3 = []
-          for (client of Array.from(clientList)) {
-            if (!seen[client.id]) {
-              seen[client.id] = true
-              result3.push(
-                client.emit(message.message, ...Array.from(message.payload))
-              )
-            } else {
-              result3.push(undefined)
-            }
+        const seen = new Map()
+        for (const client of clientList) {
+          if (!seen.has(client.id)) {
+            seen.set(client.id, true)
+            client.emit(message.message, ...message.payload)
           }
-          return result3
-        })()
-      } else if (message.health_check != null) {
+        }
+      } else if (message.health_check) {
         logger.debug(
           { message },
           'got health check message in editor events channel'
         )
-        return HealthCheckManager.check(channel, message.key)
+        HealthCheckManager.check(channel, message.key)
       }
     })
   }