diff --git a/package.json b/package.json
index b0b3ec4e46..56e1877645 100644
--- a/package.json
+++ b/package.json
@@ -72,7 +72,7 @@
     "npm": "^6"
   },
   "scripts": {
-    "lint": "eslint --ext .js --fix ./website/common",
+    "lint": "eslint --ext .js --fix ./website/server",
     "test": "npm run lint && gulp test && gulp apidoc",
     "test:build": "gulp test:prepare:build",
     "test:api-v3": "gulp test:api-v3",
diff --git a/website/server/models/challenge.js b/website/server/models/challenge.js
index b38b393be8..088211c4cc 100644
--- a/website/server/models/challenge.js
+++ b/website/server/models/challenge.js
@@ -89,12 +89,14 @@ schema.methods.canModify = function canModifyChallenge (user) {
 // Returns true if user can join the challenge
 schema.methods.canJoin = function canJoinChallenge (user, group) {
   if (group.type === 'guild' && group.privacy === 'public') return true;
-  if (this.isLeader(user)) return true; // for when leader has left private group that contains the challenge
+  // for when leader has left private group that contains the challenge
+  if (this.isLeader(user)) return true;
   return user.getGroups().indexOf(this.group) !== -1;
 };
 
 // Returns true if user can view the challenge
-// Different from canJoin because you can see challenges of groups you've been removed from if you're participating in them
+// Different from canJoin because you can see challenges of groups
+// you've been removed from if you're participating in them
 schema.methods.canView = function canViewChallenge (user, group) {
   if (this.isMember(user)) return true;
   return this.canJoin(user, group);
@@ -108,7 +110,8 @@ schema.methods.syncToUser = async function syncChallengeToUser (user) {
 
   // Add challenge to user.challenges
   if (!_.includes(user.challenges, challenge._id)) {
-    // using concat because mongoose's protection against concurrent array modification isn't working as expected.
+    // using concat because mongoose's protection against
+    // concurrent array modification isn't working as expected.
     // see https://github.com/HabitRPG/habitica/pull/7787#issuecomment-232972394
     user.challenges = user.challenges.concat([challenge._id]);
   }
@@ -119,7 +122,8 @@ schema.methods.syncToUser = async function syncChallengeToUser (user) {
   if (i !== -1) {
     if (userTags[i].name !== challenge.shortName) {
       // update the name - it's been changed since
-      // @TODO: We probably want to remove this. Owner is not allowed to change participant's copy of the tag.
+      // @TODO: We probably want to remove this.
+      // Owner is not allowed to change participant's copy of the tag.
       userTags[i].name = challenge.shortName;
     }
   } else {
@@ -150,7 +154,11 @@ schema.methods.syncToUser = async function syncChallengeToUser (user) {
 
     if (!matchingTask) { // If the task is new, create it
       matchingTask = new Tasks[chalTask.type](Tasks.Task.sanitize(syncableAttrs(chalTask)));
-      matchingTask.challenge = { taskId: chalTask._id, id: challenge._id, shortName: challenge.shortName };
+      matchingTask.challenge = {
+        taskId: chalTask._id,
+        id: challenge._id,
+        shortName: challenge.shortName,
+      };
       matchingTask.userId = user._id;
       user.tasksOrder[`${chalTask.type}s`].push(matchingTask._id);
       setNextDue(matchingTask, user);
@@ -161,8 +169,10 @@ schema.methods.syncToUser = async function syncChallengeToUser (user) {
       if (orderList.indexOf(matchingTask._id) === -1 && (matchingTask.type !== 'todo' || !matchingTask.completed)) orderList.push(matchingTask._id);
     }
 
-    if (!matchingTask.notes) matchingTask.notes = chalTask.notes; // don't override the notes, but provide it if not provided
-    if (matchingTask.tags.indexOf(challenge._id) === -1) matchingTask.tags.push(challenge._id); // add tag if missing
+    // don't override the notes, but provide it if not provided
+    if (!matchingTask.notes) matchingTask.notes = chalTask.notes;
+    // add tag if missing
+    if (matchingTask.tags.indexOf(challenge._id) === -1) matchingTask.tags.push(challenge._id);
     toSave.push(matchingTask.save());
   });
 
@@ -188,7 +198,11 @@ async function _addTaskFn (challenge, tasks, memberId) {
 
   tasks.forEach(chalTask => {
     const userTask = new Tasks[chalTask.type](Tasks.Task.sanitize(syncableAttrs(chalTask)));
-    userTask.challenge = { taskId: chalTask._id, id: challenge._id, shortName: challenge.shortName };
+    userTask.challenge = {
+      taskId: chalTask._id,
+      id: challenge._id,
+      shortName: challenge.shortName,
+    };
     userTask.userId = memberId;
 
     // We want to sync the notes and tags when the task is first added to the challenge
@@ -212,7 +226,7 @@ async function _addTaskFn (challenge, tasks, memberId) {
 
   // Update the user
   toSave.unshift(User.update({ _id: memberId }, updateTasksOrderQ).exec());
-  return await Promise.all(toSave);
+  return Promise.all(toSave);
 }
 
 // Add a new task to challenge members
@@ -237,7 +251,8 @@ schema.methods.updateTask = async function challengeUpdateTask (task) {
   }
 
   const taskSchema = Tasks[task.type];
-  // Updating instead of loading and saving for performances, risks becoming a problem if we introduce more complexity in tasks
+  // Updating instead of loading and saving for performances,
+  // risks becoming a problem if we introduce more complexity in tasks
   await taskSchema.update({
     userId: { $exists: true },
     'challenge.id': challenge.id,
@@ -268,7 +283,7 @@ schema.methods.unlinkTasks = async function challengeUnlinkTasks (user, keep, sa
   };
 
   removeFromArray(user.challenges, challengeId);
-  this.memberCount--;
+  this.memberCount -= 1;
 
   if (keep === 'keep-all') {
     await Tasks.Task.update(findQuery, {
@@ -303,7 +318,8 @@ schema.methods.unlinkTasks = async function challengeUnlinkTasks (user, keep, sa
 };
 
 // TODO everything here should be moved to a worker
-// actually even for a worker it's probably just too big and will kill mongo, figure out something else
+// actually even for a worker it's probably just too big
+// and will kill mongo, figure out something else
 schema.methods.closeChal = async function closeChal (broken = {}) {
   const challenge = this;
 
@@ -329,7 +345,10 @@ schema.methods.closeChal = async function closeChal (broken = {}) {
     // reimburse the leader
     const winnerCanGetGems = await winner.canGetGems();
     if (!winnerCanGetGems) {
-      await User.update({ _id: challenge.leader }, { $inc: { balance: challenge.prize / 4 } }).exec();
+      await User.update(
+        { _id: challenge.leader },
+        { $inc: { balance: challenge.prize / 4 } },
+      ).exec();
     } else {
       winner.balance += challenge.prize / 4;
     }
@@ -357,7 +376,8 @@ schema.methods.closeChal = async function closeChal (broken = {}) {
   const backgroundTasks = [
     // And it's tasks
     Tasks.Task.remove({ 'challenge.id': challenge._id, userId: { $exists: false } }).exec(),
-    // Set the challenge tag to non-challenge status and remove the challenge from the user's challenges
+    // Set the challenge tag to non-challenge status
+    // and remove the challenge from the user's challenges
     User.update({
       challenges: challenge._id,
       'tags.id': challenge._id,
@@ -379,4 +399,4 @@ schema.methods.closeChal = async function closeChal (broken = {}) {
   Promise.all(backgroundTasks);
 };
 
-export const model = mongoose.model('Challenge', schema);
+export const model = mongoose.model('Challenge', schema); // eslint-disable-line import/prefer-default-export
diff --git a/website/server/models/coupon.js b/website/server/models/coupon.js
index a36b1f06ea..789431ba08 100644
--- a/website/server/models/coupon.js
+++ b/website/server/models/coupon.js
@@ -28,7 +28,7 @@ schema.plugin(baseModel, {
 schema.statics.generate = async function generateCoupons (event, count = 1) {
   const coupons = _.times(count, () => ({ event }));
 
-  return await this.create(coupons);
+  return this.create(coupons);
 };
 
 schema.statics.apply = async function applyCoupon (user, req, code) {
diff --git a/website/server/models/group.js b/website/server/models/group.js
index 23cd0c00fb..9cc484f603 100644
--- a/website/server/models/group.js
+++ b/website/server/models/group.js
@@ -204,14 +204,14 @@ function _cleanQuestParty (merge) {
 // return a clean user.quest of a particular user while keeping his progress
 function _cleanQuestUser (userProgress) {
   if (!userProgress) {
-    userProgress = {
+    userProgress = { // eslint-disable-line no-param-reassign
       up: 0,
       down: 0,
       collect: {},
       collectedItems: 0,
     };
   } else {
-    userProgress = userProgress.toObject();
+    userProgress = userProgress.toObject(); // eslint-disable-line no-param-reassign
   }
 
   const clean = {
@@ -226,7 +226,8 @@ function _cleanQuestUser (userProgress) {
 
 schema.statics.getGroup = async function getGroup (options = {}) {
   const {
-    user, groupId, fields, optionalMembership = false, populateLeader = false, requireMembership = false,
+    user, groupId, fields, optionalMembership = false,
+    populateLeader = false, requireMembership = false,
   } = options;
   let query;
 
@@ -286,7 +287,7 @@ schema.statics.getGroups = async function getGroups (options = {}) {
   if (!areValidTypes) throw new BadRequest(shared.i18n.t('groupTypesRequired'));
 
   types.forEach(type => {
-    switch (type) {
+    switch (type) { // eslint-disable-line default-case
       case 'party': {
         queries.push(this.getGroup({
           user, groupId: 'party', fields: groupFields, populateLeader,
@@ -318,7 +319,8 @@ schema.statics.getGroups = async function getGroups (options = {}) {
         queries.push(privateGuildsQuery);
         break;
       }
-      // NOTE: when returning publicGuilds we use `.lean()` so all mongoose methods won't be available.
+      // NOTE: when returning publicGuilds we use `.lean()` so all
+      // mongoose methods won't be available.
       // Docs are going to be plain javascript objects
       case 'publicGuilds': {
         const query = {
@@ -326,11 +328,16 @@ schema.statics.getGroups = async function getGroups (options = {}) {
           privacy: 'public',
         };
         _.assign(query, filters);
+
         const publicGuildsQuery = this.find(query).select(groupFields);
+
         if (populateLeader === true) publicGuildsQuery.populate('leader', nameFields);
-        if (paginate === true) publicGuildsQuery.limit(GUILDS_PER_PAGE).skip(page * GUILDS_PER_PAGE);
+        if (paginate === true) {
+          publicGuildsQuery.limit(GUILDS_PER_PAGE).skip(page * GUILDS_PER_PAGE);
+        }
         publicGuildsQuery.sort(sort).lean().exec();
         queries.push(publicGuildsQuery);
+
         break;
       }
       case 'tavern': {
@@ -343,8 +350,10 @@ schema.statics.getGroups = async function getGroups (options = {}) {
   });
 
   const groupsArray = _.reduce(await Promise.all(queries), (previousValue, currentValue) => {
-    if (_.isEmpty(currentValue)) return previousValue; // don't add anything to the results if the query returned null or an empty array
-    return previousValue.concat(Array.isArray(currentValue) ? currentValue : [currentValue]); // otherwise concat the new results to the previousValue
+    // don't add anything to the results if the query returned null or an empty array
+    if (_.isEmpty(currentValue)) return previousValue;
+    // otherwise concat the new results to the previousValue
+    return previousValue.concat(Array.isArray(currentValue) ? currentValue : [currentValue]);
   }, []);
 
   return groupsArray;
@@ -355,7 +364,8 @@ schema.statics.getGroups = async function getGroups (options = {}) {
 // Not putting into toJSON because there we can't access user
 // It also removes the _meta field that can be stored inside a chat message
 schema.statics.toJSONCleanChat = async function groupToJSONCleanChat (group, user) {
-  // @TODO: Adding this here for support the old chat, but we should depreciate accessing chat like this
+  // @TODO: Adding this here for support the old chat,
+  // but we should depreciate accessing chat like this
   // Also only return chat if requested, eventually we don't want to return chat here
   if (group && group.chat) {
     await getGroupChat(group);
@@ -384,7 +394,9 @@ schema.statics.toJSONCleanChat = async function groupToJSONCleanChat (group, use
         if (chatMsg._meta) chatMsg._meta = undefined;
 
         // Messages with too many flags are hidden to non-admins and non-authors
-        if (user._id !== chatMsg.uuid && chatMsg.flagCount >= CHAT_FLAG_LIMIT_FOR_HIDING) return undefined;
+        if (user._id !== chatMsg.uuid && chatMsg.flagCount >= CHAT_FLAG_LIMIT_FOR_HIDING) {
+          return undefined;
+        }
       }
 
       return chatMsg;
@@ -442,7 +454,7 @@ function getInviteCount (uuids, emails) {
  * @param  res  Express res object for use with translations
  * @throws BadRequest An error describing the issue with the invitations
  */
-schema.statics.validateInvitations = async function getInvitationError (invites, res, group = null) {
+schema.statics.validateInvitations = async function getInvitationErr (invites, res, group = null) {
   const {
     uuids,
     emails,
@@ -493,7 +505,8 @@ schema.methods.removeGroupInvitations = async function removeGroupInvitations ()
   const userUpdates = usersToRemoveInvitationsFrom.map(user => {
     if (group.type === 'party') {
       removeFromArray(user.invitations.parties, { id: group._id });
-      user.invitations.party = user.invitations.parties.length > 0 ? user.invitations.parties[user.invitations.parties.length - 1] : {};
+      user.invitations.party = user.invitations.parties.length > 0
+        ? user.invitations.parties[user.invitations.parties.length - 1] : {};
       this.markModified('invitations.party');
     } else {
       removeFromArray(user.invitations.guilds, { id: group._id });
@@ -521,7 +534,7 @@ schema.methods.getMemberCount = async function getMemberCount () {
     query = { 'party._id': this._id };
   }
 
-  return await User.count(query).exec();
+  return User.count(query).exec();
 };
 
 schema.methods.sendChat = function sendChat (options = {}) {
@@ -549,7 +562,11 @@ schema.methods.sendChat = function sendChat (options = {}) {
   // - groups that never send notifications (e.g., Tavern)
   // - groups with very many users
   // - messages that have already been flagged to hide them
-  if (NO_CHAT_NOTIFICATIONS.indexOf(this._id) !== -1 || this.memberCount > LARGE_GROUP_COUNT_MESSAGE_CUTOFF || newChatMessage.flagCount >= CHAT_FLAG_LIMIT_FOR_HIDING) {
+  if (
+    NO_CHAT_NOTIFICATIONS.indexOf(this._id) !== -1
+    || this.memberCount > LARGE_GROUP_COUNT_MESSAGE_CUTOFF
+    || newChatMessage.flagCount >= CHAT_FLAG_LIMIT_FOR_HIDING
+  ) {
     return newChatMessage;
   }
 
@@ -597,7 +614,8 @@ schema.methods.sendChat = function sendChat (options = {}) {
 };
 
 schema.methods.startQuest = async function startQuest (user) {
-  // not using i18n strings because these errors are meant for devs who forgot to pass some parameters
+  // not using i18n strings because these errors are meant
+  // for devs who forgot to pass some parameters
   if (this.type !== 'party') throw new InternalServerError('Must be a party to use this method');
   if (!this.quest.key) throw new InternalServerError('Party does not have a pending quest');
   if (this.quest.active) throw new InternalServerError('Quest is already active');
@@ -786,7 +804,7 @@ function _getUserUpdateForQuestReward (itemToAward, allAwardedItems) {
   };
   const dropK = itemToAward.key;
 
-  switch (itemToAward.type) {
+  switch (itemToAward.type) { // eslint-disable-line default-case
     case 'gear': {
       // TODO This means they can lose their new gear on death, is that what we want?
       updates.$set[`items.gear.owned.${dropK}`] = true;
@@ -860,7 +878,7 @@ schema.methods.finishQuest = async function finishQuest (quest) {
   this.markModified('quest');
 
   if (this._id === TAVERN_ID) {
-    return await User.update({}, updates, { multi: true }).exec();
+    return User.update({}, updates, { multi: true }).exec();
   }
 
   const promises = participants.map(userId => {
@@ -921,15 +939,18 @@ schema.methods.finishQuest = async function finishQuest (quest) {
         }).toObject(),
       };
 
-      promises.push(participants.map(userId => _updateUserWithRetries(userId, questAchievementUpdate, null, questAchievementQuery)));
+      promises.push(participants.map(userId => _updateUserWithRetries(
+        userId, questAchievementUpdate, null, questAchievementQuery,
+      )));
     }
   });
 
-  await Promise.all(promises);
+  return Promise.all(promises);
 };
 
 function _isOnQuest (user, progress, group) {
-  return group && progress && group.quest && group.quest.active && group.quest.members[user._id] === true;
+  return group && progress && group.quest && group.quest.active
+    && group.quest.members[user._id] === true;
 }
 
 schema.methods._processBossQuest = async function processBossQuest (options) {
@@ -989,8 +1010,11 @@ schema.methods._processBossQuest = async function processBossQuest (options) {
       promises.push(rageMessage.save());
       group.quest.progress.rage = 0;
 
-      // TODO To make Rage effects more expandable, let's turn these into functions in quest.boss.rage
-      if (quest.boss.rage.healing) group.quest.progress.hp += group.quest.progress.hp * quest.boss.rage.healing;
+      // TODO To make Rage effects more expandable,
+      // let's turn these into functions in quest.boss.rage
+      if (quest.boss.rage.healing) {
+        group.quest.progress.hp += group.quest.progress.hp * quest.boss.rage.healing;
+      }
       if (group.quest.progress.hp > quest.boss.hp) group.quest.progress.hp = quest.boss.hp;
       if (quest.boss.rage.mpDrain) {
         updates.$set = { 'stats.mp': 0 };
@@ -1006,10 +1030,13 @@ schema.methods._processBossQuest = async function processBossQuest (options) {
     updates,
     { multi: true },
   ).exec();
-  // Apply changes the currently cronning user locally so we don't have to reload it to get the updated state
+  // Apply changes the currently cronning user locally
+  // so we don't have to reload it to get the updated state
   // TODO how to mark not modified? https://github.com/Automattic/mongoose/pull/1167
-  // must be notModified or otherwise could overwrite future changes: if the user is saved it'll save
-  // the modified user.stats.hp but that must not happen as the hp value has already been updated by the User.update above
+  // must be notModified or otherwise could overwrite future changes:
+  // if the user is saved it'll save
+  // the modified user.stats.hp but that must not happen as the hp value has already been updated
+  // by the User.update above
   // if (down) user.stats.hp += down;
 
   // Boss slain, finish quest
@@ -1028,7 +1055,7 @@ schema.methods._processBossQuest = async function processBossQuest (options) {
   }
 
   promises.unshift(group.save());
-  return await Promise.all(promises);
+  return Promise.all(promises);
 };
 
 schema.methods._processCollectionQuest = async function processCollectionQuest (options) {
@@ -1041,7 +1068,8 @@ schema.methods._processCollectionQuest = async function processCollectionQuest (
   const quest = questScrolls[group.quest.key];
   const itemsFound = {};
 
-  const possibleItemKeys = Object.keys(quest.collect).filter(key => group.quest.progress.collect[key] !== quest.collect[key].count);
+  const possibleItemKeys = Object.keys(quest.collect)
+    .filter(key => group.quest.progress.collect[key] !== quest.collect[key].count);
 
   const possibleItemsToCollect = possibleItemKeys.reduce((accumulator, current, index) => {
     accumulator[possibleItemKeys[index]] = quest.collect[current];
@@ -1054,8 +1082,8 @@ schema.methods._processCollectionQuest = async function processCollectionQuest (
     if (!itemsFound[item]) {
       itemsFound[item] = 0;
     }
-    itemsFound[item]++;
-    group.quest.progress.collect[item]++;
+    itemsFound[item] += 1;
+    group.quest.progress.collect[item] += 1;
   });
 
   // Add 0 for all items not found
@@ -1086,7 +1114,7 @@ schema.methods._processCollectionQuest = async function processCollectionQuest (
   const needsCompleted = _.find(quest.collect, (v, k) => group.quest.progress.collect[k] < v.count);
 
   if (needsCompleted) {
-    return await Promise.all([group.save(), foundChat.save()]);
+    return Promise.all([group.save(), foundChat.save()]);
   }
 
   await group.finishQuest(quest);
@@ -1099,7 +1127,7 @@ schema.methods._processCollectionQuest = async function processCollectionQuest (
 
   const promises = [group.save(), foundChat.save(), allItemsFoundChat.save()];
 
-  return await Promise.all(promises);
+  return Promise.all(promises);
 };
 
 schema.statics.processQuestProgress = async function processQuestProgress (user, progress) {
@@ -1122,7 +1150,9 @@ schema.statics.processQuestProgress = async function processQuestProgress (user,
   });
 };
 
-// to set a boss: `db.groups.update({_id:TAVERN_ID},{$set:{quest:{key:'dilatory',active:true,progress:{hp:1000,rage:1500}}}}).exec()`
+// to set a boss:
+// `db.groups.update({_id:TAVERN_ID},
+// {$set:{quest:{key:'dilatory',active:true,progress:{hp:1000,rage:1500}}}}).exec()`
 // we export an empty object that is then populated with the query-returned data
 export const tavernQuest = {};
 const tavernQ = { _id: TAVERN_ID, 'quest.key': { $ne: null } };
@@ -1144,15 +1174,15 @@ process.nextTick(() => {
 
 // returns a promise
 schema.statics.tavernBoss = async function tavernBoss (user, progress) {
-  if (!progress) return;
-  if (user.preferences.sleep) return;
+  if (!progress) return null;
+  if (user.preferences.sleep) return null;
 
   // hack: prevent crazy damage to world boss
   const dmg = Math.min(900, Math.abs(progress.up || 0));
   const rage = -Math.min(900, Math.abs(progress.down || 0));
 
   const tavern = await this.findOne(tavernQ).exec();
-  if (!(tavern && tavern.quest && tavern.quest.key)) return;
+  if (!(tavern && tavern.quest && tavern.quest.key)) return null;
 
   const quest = shared.content.quests[tavern.quest.key];
 
@@ -1171,7 +1201,9 @@ schema.statics.tavernBoss = async function tavernBoss (user, progress) {
     _.assign(tavernQuest, { extra: null });
     return tavern.save();
   }
-  // Deal damage. Note a couple things here, str & def are calculated. If str/def are defined in the database,
+
+  // Deal damage. Note a couple things here, str & def are calculated.
+  // If str/def are defined in the database,
   // use those first - which allows us to update the boss on the go if things are too easy/hard.
   if (!tavern.quest.extra) tavern.quest.extra = {};
   tavern.quest.progress.hp -= dmg / (tavern.quest.extra.def || quest.boss.def);
@@ -1222,7 +1254,11 @@ schema.statics.tavernBoss = async function tavernBoss (user, progress) {
     }
   }
 
-  if (quest.boss.desperation && tavern.quest.progress.hp < quest.boss.desperation.threshold && !tavern.quest.extra.desperate) {
+  if (
+    quest.boss.desperation
+    && tavern.quest.progress.hp < quest.boss.desperation.threshold
+    && !tavern.quest.extra.desperate
+  ) {
     const progressChat = tavern.sendChat({
       message: quest.boss.desperation.text('en'),
       info: {
@@ -1272,7 +1308,8 @@ schema.methods.leave = async function leaveGroup (user, keep = 'keep-all', keepC
     userId: { $exists: false },
     'group.assignedUsers': user._id,
   }).exec();
-  const assignedTasksToRemoveUserFrom = assignedTasks.map(task => this.unlinkTask(task, user, keep, false));
+  const assignedTasksToRemoveUserFrom = assignedTasks
+    .map(task => this.unlinkTask(task, user, keep, false));
   await Promise.all(assignedTasksToRemoveUserFrom);
 
   // the user could be modified by calls to `unlinkTask` for challenge and group tasks
@@ -1294,7 +1331,8 @@ schema.methods.leave = async function leaveGroup (user, keep = 'keep-all', keepC
 
   // If user is the last one in group and group is private, delete it
   if (group.memberCount <= 1 && group.privacy === 'private') {
-    // double check the member count is correct so we don't accidentally delete a group that still has users in it
+    // double check the member count is correct
+    // so we don't accidentally delete a group that still has users in it
     let members;
     if (group.type === 'guild') {
       members = await User.find({ guilds: group._id }).select('_id').exec();
@@ -1306,37 +1344,44 @@ schema.methods.leave = async function leaveGroup (user, keep = 'keep-all', keepC
 
     if (members.length === 0) {
       promises.push(group.remove());
-      return await Promise.all(promises);
+      return Promise.all(promises);
     }
-  } else if (group.leader === user._id) { // otherwise If the leader is leaving (or if the leader previously left, and this wasn't accounted for)
+  // otherwise If the leader is leaving
+  // (or if the leader previously left, and this wasn't accounted for)
+  } else if (group.leader === user._id) {
     const query = group.type === 'party' ? { 'party._id': group._id } : { guilds: group._id };
     query._id = { $ne: user._id };
     const seniorMember = await User.findOne(query).select('_id').exec();
 
-    // could be missing in case of public guild (that can have 0 members) with 1 member who is leaving
+    // could be missing in case of public guild (that can have 0 members)
+    // with 1 member who is leaving
     if (seniorMember) update.$set = { leader: seniorMember._id };
   }
-  // otherwise If the leader is leaving (or if the leader previously left, and this wasn't accounted for)
+  // otherwise If the leader is leaving
+  // (or if the leader previously left, and this wasn't accounted for)
   update.$inc = { memberCount: -1 };
   if (group.leader === user._id) {
     const query = group.type === 'party' ? { 'party._id': group._id } : { guilds: group._id };
     query._id = { $ne: user._id };
     const seniorMember = await User.findOne(query).select('_id').exec();
 
-    // could be missing in case of public guild (that can have 0 members) with 1 member who is leaving
+    // could be missing in case of public guild (that can have 0 members)
+    // with 1 member who is leaving
     if (seniorMember) update.$set = { leader: seniorMember._id };
   }
   promises.push(group.update(update).exec());
 
-  return await Promise.all(promises);
+  return Promise.all(promises);
 };
 
 /**
  * Updates all linked tasks for a group task
  *
  * @param  taskToSync  The group task that will be synced
- * @param  options.newCheckListItem  The new checklist item that needs to be synced to all assigned users
- * @param  options.removedCheckListItem  The removed checklist item that needs to be removed from all assigned users
+ * @param  options.newCheckListItem  The new checklist item
+ *          that needs to be synced to all assigned users
+ * @param  options.removedCheckListItem  The removed checklist item that
+ *          needs to be removed from all assigned users
  *
  * @return The created tasks
  */
@@ -1395,7 +1440,8 @@ schema.methods.updateTask = async function updateTask (taskToSync, options = {})
     return;
   }
 
-  // Updating instead of loading and saving for performances, risks becoming a problem if we introduce more complexity in tasks
+  // Updating instead of loading and saving for performances,
+  // risks becoming a problem if we introduce more complexity in tasks
   await taskSchema.update(updateQuery, updateCmd, { multi: true }).exec();
 };
 
@@ -1461,14 +1507,19 @@ schema.methods.syncTask = async function groupSyncTask (taskToSync, user) {
     });
   }
 
-  if (!matchingTask.notes) matchingTask.notes = taskToSync.notes; // don't override the notes, but provide it if not provided
-  if (matchingTask.tags.indexOf(group._id) === -1) matchingTask.tags.push(group._id); // add tag if missing
+  // don't override the notes, but provide it if not provided
+  if (!matchingTask.notes) matchingTask.notes = taskToSync.notes;
+  // add tag if missing
+  if (matchingTask.tags.indexOf(group._id) === -1) matchingTask.tags.push(group._id);
 
   toSave.push(matchingTask.save(), taskToSync.save(), user.save());
   return Promise.all(toSave);
 };
 
-schema.methods.unlinkTask = async function groupUnlinkTask (unlinkingTask, user, keep, saveUser = true) {
+schema.methods.unlinkTask = async function groupUnlinkTask (
+  unlinkingTask, user,
+  keep, saveUser = true,
+) {
   const findQuery = {
     'group.taskId': unlinkingTask._id,
     userId: user._id,
@@ -1501,7 +1552,7 @@ schema.methods.unlinkTask = async function groupUnlinkTask (unlinkingTask, user,
     // save the user once outside of this function
     if (saveUser) promises.push(user.save());
 
-    return Promise.all(promises);
+    await Promise.all(promises);
   }
 };
 
@@ -1537,7 +1588,7 @@ schema.methods.removeTask = async function groupRemoveTask (task) {
   group.markModified('tasksOrder');
   removalPromises.push(group.save());
 
-  return await Promise.all(removalPromises);
+  return Promise.all(removalPromises);
 };
 
 // Returns true if the user has reached the spam message limit
@@ -1550,10 +1601,10 @@ schema.methods.checkChatSpam = function groupCheckChatSpam (user) {
 
   const currentTime = Date.now();
   let userMessages = 0;
-  for (let i = 0; i < this.chat.length; i++) {
+  for (let i = 0; i < this.chat.length; i += 1) {
     const message = this.chat[i];
     if (message.uuid === user._id && currentTime - message.timestamp <= SPAM_WINDOW_LENGTH) {
-      userMessages++;
+      userMessages += 1;
       if (userMessages >= SPAM_MESSAGE_LIMIT) {
         return true;
       }
@@ -1568,7 +1619,8 @@ schema.methods.checkChatSpam = function groupCheckChatSpam (user) {
 schema.methods.isSubscribed = function isSubscribed () {
   const now = new Date();
   const { plan } = this.purchased;
-  return plan && plan.customerId && (!plan.dateTerminated || moment(plan.dateTerminated).isAfter(now));
+  return plan && plan.customerId
+    && (!plan.dateTerminated || moment(plan.dateTerminated).isAfter(now));
 };
 
 schema.methods.hasNotCancelled = function hasNotCancelled () {
@@ -1593,12 +1645,15 @@ schema.methods.updateGroupPlan = async function updateGroupPlan (removingMember)
 
   if (this.purchased.plan.paymentMethod === stripePayments.constants.PAYMENT_METHOD) {
     await stripePayments.chargeForAdditionalGroupMember(this);
-  } else if (this.purchased.plan.paymentMethod === amazonPayments.constants.PAYMENT_METHOD && !removingMember) {
+  } else if (
+    this.purchased.plan.paymentMethod === amazonPayments.constants.PAYMENT_METHOD
+    && !removingMember
+  ) {
     await amazonPayments.chargeForAdditionalGroupMember(this);
   }
 };
 
-export let model = mongoose.model('Group', schema);
+export const model = mongoose.model('Group', schema);
 
 // initialize tavern if !exists (fresh installs)
 // do not run when testing as it's handled by the tests and can easily cause a race condition
diff --git a/website/server/models/message.js b/website/server/models/message.js
index 5a267d831a..1fdea935ce 100644
--- a/website/server/models/message.js
+++ b/website/server/models/message.js
@@ -128,7 +128,8 @@ export function messageDefaults (msg, user, client, flagCount = 0, info = {}) {
       contributor: user.contributor && user.contributor.toObject(),
       backer: user.backer && user.backer.toObject(),
       user: user.profile.name,
-      username: user.flags && user.flags.verifiedUsername && user.auth && user.auth.local && user.auth.local.username,
+      username: user.flags && user.flags.verifiedUsername
+        && user.auth && user.auth.local && user.auth.local.username,
     });
   } else {
     message.uuid = 'system';
diff --git a/website/server/models/subscriptionPlan.js b/website/server/models/subscriptionPlan.js
index 935fabb66d..d59e10b14f 100644
--- a/website/server/models/subscriptionPlan.js
+++ b/website/server/models/subscriptionPlan.js
@@ -17,12 +17,16 @@ export const schema = new mongoose.Schema({
   mysteryItems: { $type: Array, default: () => [] },
   lastReminderDate: Date, // indicates the last time a subscription reminder was sent
   lastBillingDate: Date, // Used only for Amazon Payments to keep track of billing date
-  additionalData: mongoose.Schema.Types.Mixed, // Example for Google: {'receipt': 'serialized receipt json', 'signature': 'signature string'}
-  nextPaymentProcessing: Date, // indicates when the queue server should process this subscription again.
+  // Example for Google: {'receipt': 'serialized receipt json', 'signature': 'signature string'}
+  additionalData: mongoose.Schema.Types.Mixed,
+  // indicates when the queue server should process this subscription again.
+  nextPaymentProcessing: Date,
   nextBillingDate: Date, // Next time google will bill this user.
   consecutive: {
     count: { $type: Number, default: 0 },
-    offset: { $type: Number, default: 0 }, // when gifted subs, offset++ for each month. offset-- each new-month (cron). count doesn't ++ until offset==0
+    // when gifted subs, offset++ for each month. offset-- each new-month (cron).
+    // count doesn't ++ until offset==0
+    offset: { $type: Number, default: 0 },
     gemCapExtra: { $type: Number, default: 0 },
     trinkets: { $type: Number, default: 0 },
   },
diff --git a/website/server/models/task.js b/website/server/models/task.js
index 89e84da05c..c6fba9af2f 100644
--- a/website/server/models/task.js
+++ b/website/server/models/task.js
@@ -56,8 +56,9 @@ reminderSchema.plugin(baseModel, {
   _id: false,
 });
 
-// Important
-// When something changes here remember to update the client side model at common/script/libs/taskDefaults
+// NOTE IMPORTANTE
+// When something changes here remember to update the client side model
+// at common/script/libs/taskDefaults
 export const TaskSchema = new Schema({
   type: {
     $type: String, enum: tasksTypes, required: true, default: tasksTypes[0],
@@ -94,7 +95,8 @@ export const TaskSchema = new Schema({
     $type: String,
     validate: [v => validator.isUUID(v), 'Invalid uuid.'],
   }],
-  value: { $type: Number, default: 0, required: true }, // redness or cost for rewards Required because it must be settable (for rewards)
+  // redness or cost for rewards Required because it must be settable (for rewards)
+  value: { $type: Number, default: 0, required: true },
   priority: {
     $type: Number,
     default: 1,
@@ -129,7 +131,11 @@ export const TaskSchema = new Schema({
       requested: { $type: Boolean, default: false },
       requestedDate: { $type: Date },
     },
-    sharedCompletion: { $type: String, enum: _.values(SHARED_COMPLETION), default: SHARED_COMPLETION.single },
+    sharedCompletion: {
+      $type: String,
+      enum: _.values(SHARED_COMPLETION),
+      default: SHARED_COMPLETION.single,
+    },
   },
 
   reminders: [reminderSchema],
@@ -162,8 +168,13 @@ TaskSchema.plugin(baseModel, {
   timestamps: true,
 });
 
-TaskSchema.statics.findByIdOrAlias = async function findByIdOrAlias (identifier, userId, additionalQueries = {}) {
-  // not using i18n strings because these errors are meant for devs who forgot to pass some parameters
+TaskSchema.statics.findByIdOrAlias = async function findByIdOrAlias (
+  identifier,
+  userId,
+  additionalQueries = {},
+) {
+  // not using i18n strings because these errors
+  // are meant for devs who forgot to pass some parameters
   if (!identifier) throw new InternalServerError('Task identifier is a required argument');
   if (!userId) throw new InternalServerError('User identifier is a required argument');
 
@@ -224,7 +235,8 @@ TaskSchema.methods.scoreChallengeTask = async function scoreChallengeTask (delta
       lastHistoryEntry.date = Number(new Date());
 
       if (chalTask.type === 'habit') {
-        // @TODO remove this extra check after migration has run to set scoredUp and scoredDown in every task
+        // @TODO remove this extra check after migration has run to set scoredUp and scoredDown
+        // in every task
         lastHistoryEntry.scoredUp = lastHistoryEntry.scoredUp || 0;
         lastHistoryEntry.scoredDown = lastHistoryEntry.scoredDown || 0;
 
@@ -251,7 +263,8 @@ TaskSchema.methods.scoreChallengeTask = async function scoreChallengeTask (delta
 
       // Only preen task history once a day when the task is scored first
       if (chalTask.history.length > 365) {
-        chalTask.history = preenHistory(chalTask.history, true); // true means the challenge will retain as many entries as a subscribed user
+        // true means the challenge will retain as many entries as a subscribed user
+        chalTask.history = preenHistory(chalTask.history, true);
       }
     }
   }
@@ -259,16 +272,15 @@ TaskSchema.methods.scoreChallengeTask = async function scoreChallengeTask (delta
   await chalTask.save();
 };
 
-export let Task = mongoose.model('Task', TaskSchema);
+export const Task = mongoose.model('Task', TaskSchema);
 
 // habits and dailies shared fields
-const habitDailySchema = () =>
-  // Schema not defined because it causes serious perf problems
-  // date is a date stored as a Number value
-  // value is a Number
-  // scoredUp and scoredDown only exist for habits and are numbers
-  ({ history: Array })
-;
+// Schema for history not defined because it causes serious perf problems
+// date is a date stored as a Number value
+// value is a Number
+// scoredUp and scoredDown only exist for habits and are numbers
+
+const habitDailySchema = () => ({ history: Array });
 
 // dailys and todos shared fields
 const dailyTodoSchema = () => ({
@@ -322,8 +334,10 @@ export const DailySchema = new Schema(_.defaults({
     su: { $type: Boolean, default: true },
   },
   streak: { $type: Number, default: 0 },
-  daysOfMonth: { $type: [Number], default: [] }, // Days of the month that the daily should repeat on
-  weeksOfMonth: { $type: [Number], default: [] }, // Weeks of the month that the daily should repeat on
+  // Days of the month that the daily should repeat on
+  daysOfMonth: { $type: [Number], default: [] },
+  // Weeks of the month that the daily should repeat on
+  weeksOfMonth: { $type: [Number], default: [] },
   isDue: { $type: Boolean },
   nextDue: [{ $type: String }],
   yesterDaily: { $type: Boolean, default: true, required: true },
diff --git a/website/server/models/userNotification.js b/website/server/models/userNotification.js
index 2e24d99afd..0568b3015a 100644
--- a/website/server/models/userNotification.js
+++ b/website/server/models/userNotification.js
@@ -83,7 +83,7 @@ export const schema = new Schema({
  * @TODO Remove once https://github.com/HabitRPG/habitica/issues/9923
  * is fixed
  */
-schema.statics.convertNotificationsToSafeJson = function convertNotificationsToSafeJson (notifications) {
+schema.statics.convertNotificationsToSafeJson = function convNotifsToSafeJson (notifications) {
   if (!notifications) return notifications;
 
   let filteredNotifications = notifications.filter(n => {