diff --git a/app/javascript/packs/application.js b/app/javascript/packs/application.js
index 24201afe5..37ff9664b 100644
--- a/app/javascript/packs/application.js
+++ b/app/javascript/packs/application.js
@@ -1,4 +1,5 @@
 /* eslint no-console:0 */
+/* global require */
 
 function importAll(r) {
   r.keys().forEach(r);
@@ -36,4 +37,4 @@ export { default as Dtext } from '../src/javascripts/dtext.js';
 export { default as Note } from '../src/javascripts/notes.js';
 export { default as PostModeMenu } from '../src/javascripts/post_mode_menu.js';
 export { default as Utility } from '../src/javascripts/utility.js';
-export { default as Ugoira } from '../src/javascripts/ugoira.js';
\ No newline at end of file
+export { default as Ugoira } from '../src/javascripts/ugoira.js';
diff --git a/app/javascript/src/javascripts/artist_commentaries.js b/app/javascript/src/javascripts/artist_commentaries.js
index e111dba67..70f20af86 100644
--- a/app/javascript/src/javascripts/artist_commentaries.js
+++ b/app/javascript/src/javascripts/artist_commentaries.js
@@ -63,15 +63,16 @@ ArtistCommentary.initialize_edit_commentary_dialog = function() {
 }
 
 ArtistCommentary.fetch_commentary = function() {
+  var commentary = "";
   Utility.notice("Fetching artist commentary...");
 
   var type = $('#fetch-commentary select[name="commentary_source_type"]').val();
   if (type === "Source") {
     var source = $('#fetch-commentary input[name="commentary_source"]').val();
-    var commentary = ArtistCommentary.from_source(source);
+    commentary = ArtistCommentary.from_source(source);
   } else if (type === "Post") {
     var id = $('#fetch-commentary input[name="commentary_post_id"]').val();
-    var commentary = ArtistCommentary.from_post_id(id);
+    commentary = ArtistCommentary.from_post_id(id);
   }
 
   commentary.then(ArtistCommentary.fill_commentary).then(function (success) {
@@ -120,13 +121,13 @@ ArtistCommentary.merge_commentaries = function(description, commentary) {
   var normalized_source = $("#image-container").data().normalizedSource;
 
   if ((commentary.original_description && description) &&
-      (commentary.original_description != description)) {
+      (commentary.original_description !== description)) {
     return description
       + "\n\n[tn]\nSource: " + normalized_source + "\n[/tn]"
       + "\n\nh6. " + (commentary.original_title || "Untitled")
       + "\n\n" + commentary.original_description
       + "\n\n[tn]\nSource: " + commentary.source + "\n[/tn]";
-  } else if (commentary.source != post_source) {
+  } else if (commentary.source !== post_source) {
     return commentary.original_description + "\n\n[tn]\nSource: " + commentary.source + "\n[/tn]";
   } else {
     return commentary.original_description || description;
diff --git a/app/javascript/src/javascripts/artists.js b/app/javascript/src/javascripts/artists.js
index 88dd0068e..83a8784df 100644
--- a/app/javascript/src/javascripts/artists.js
+++ b/app/javascript/src/javascripts/artists.js
@@ -14,10 +14,10 @@ Artist.initialize_check_name = function() {
     if ($("#artist_name").val().length > 0) {
       $("#check-name-result").html("");
 
-      $.getJSON("/artists?search[name]=" + escape($("#artist_name").val()), function(data) {
-        if (data.length === 0) {
-          $.getJSON("/wiki_pages/" + escape($("#artist_name").val()), function(data) {
-            if (data !== null) {
+      $.getJSON("/artists?search[name]=" + escape($("#artist_name").val()), function(artists) {
+        if (artists.length === 0) {
+          $.getJSON("/wiki_pages/" + escape($("#artist_name").val()), function(wiki_pages) {
+            if (wiki_pages !== null) {
               $("#check-name-result").html("<a href='/wiki_pages/" + escape($("#artist_name").val()) + "'>A wiki page with this name already exists</a>. You must either move the wiki page or pick another artist name.")
             }
           });
diff --git a/app/javascript/src/javascripts/autocomplete.js.erb b/app/javascript/src/javascripts/autocomplete.js.erb
index 11a0fcb33..bd67ac744 100644
--- a/app/javascript/src/javascripts/autocomplete.js.erb
+++ b/app/javascript/src/javascripts/autocomplete.js.erb
@@ -3,9 +3,12 @@ import SavedSearch from './saved_searches'
 
 let Autocomplete = {};
 
-Autocomplete.AUTOCOMPLETE_VERSION = 1;
-Autocomplete.PREFIXES = /^(-|~|<%= TagCategory.mapping.keys.map {|category| category + ':'}.join('|') %>)(.*)$/i;
-Autocomplete.METATAGS = /^(<%= Tag::METATAGS %>):(.*)$/i;
+Autocomplete.METATAGS = <%= Tag::METATAGS.to_json.html_safe %>;
+Autocomplete.TAG_CATEGORIES = <%= TagCategory.mapping.to_json.html_safe %>;
+
+Autocomplete.TAG_PREFIXES = "-|~|" + Object.keys(Autocomplete.TAG_CATEGORIES).map(category => category + ":").join("|");
+Autocomplete.TAG_PREFIXES_REGEX = new RegExp("^(" + Autocomplete.TAG_PREFIXES + ")(.*)$", "i");
+Autocomplete.METATAGS_REGEX = new RegExp("^(" + Autocomplete.METATAGS + "):(.*)$", "i");
 
 Autocomplete.initialize_all = function() {
   if (Utility.meta("enable-auto-complete") === "true") {
@@ -42,16 +45,15 @@ Autocomplete.initialize_mention_autocomplete = function($fields) {
     },
     source: function(req, resp) {
       var cursor = this.element.get(0).selectionStart;
-      var i;
       var name = null;
 
-      for (i=cursor; i>=1; --i) {
-        if (req.term[i-1] === " ") {
+      for (var i = cursor; i >= 1; --i) {
+        if (req.term[i - 1] === " ") {
           return;
         }
 
-        if (req.term[i-1] === "@") {
-          if (i == 1 || /[ \r\n]/.test(req.term[i-2])) {
+        if (req.term[i - 1] === "@") {
+          if (i === 1 || /[ \r\n]/.test(req.term[i - 2])) {
             name = req.term.substring(i, cursor);
             break;
           } else {
@@ -63,8 +65,6 @@ Autocomplete.initialize_mention_autocomplete = function($fields) {
       if (name) {
         Autocomplete.user_source(name, resp, "@");
       }
-
-      return;
     }
   });
 }
@@ -99,7 +99,7 @@ Autocomplete.initialize_tag_autocomplete = function() {
         return;
       }
 
-      switch(metatag) {
+      switch (metatag) {
       case "md5":
       case "width":
       case "height":
@@ -117,7 +117,7 @@ Autocomplete.initialize_tag_autocomplete = function() {
       case "pixiv_id":
       case "pixiv":
       <% TagCategory.short_name_list.each do |category| %>
-        case "<%= category %>tags":
+        case "<%= category %>tags": // eslint-disable-line
       <% end %>
         resp([]);
         return;
@@ -194,7 +194,7 @@ Autocomplete.initialize_artist_autocomplete = function($fields) {
               type: "tag",
               label: artist.name.replace(/_/g, " "),
               value: artist.name,
-              category: <%= Tag.categories.artist %>,
+              category: Autocomplete.TAG_CATEGORIES.artist,
             };
           }));
         }
@@ -250,9 +250,7 @@ Autocomplete.normal_source = function(term, resp) {
     return window.Danbooru.Autocomplete.normal_source(term, resp);
   }
 
-  var key = "ac-" + term.replace(/\./g,'\uFFFF');
-
-  $.ajax({
+  return $.ajax({
     url: "/tags/autocomplete.json",
     data: {
       "search[name_matches]": term,
@@ -288,12 +286,14 @@ Autocomplete.parse_query = function(text, caret) {
     return {};
   }
 
-  if (match = term.match(Autocomplete.PREFIXES)) {
+  match = term.match(Autocomplete.TAG_PREFIXES_REGEX);
+  if (match) {
     metatag = match[1].toLowerCase();
     term = match[2];
   }
-  
-  if (match = term.match(Autocomplete.METATAGS)) {
+
+  match = term.match(Autocomplete.METATAGS_REGEX);
+  if (match) {
     metatag = match[1].toLowerCase();
     term = match[2];
   }
@@ -307,8 +307,7 @@ Autocomplete.insert_completion = function(input, completion) {
   var before_caret_text = input.value.substring(0, input.selectionStart).trim();
   var after_caret_text = input.value.substring(input.selectionStart).trim();
 
-  var prefixes = "-|~|" + "<%= TagCategory.mapping.keys.map {|category| category + ':'}.join('|') %>";
-  var regexp = new RegExp("(" + prefixes + ")?\\S+$", "g");
+  var regexp = new RegExp("(" + Autocomplete.TAG_PREFIXES + ")?\\S+$", "g");
   before_caret_text = before_caret_text.replace(regexp, "$1") + completion + " ";
 
   input.value = before_caret_text + after_caret_text;
@@ -357,12 +356,12 @@ Autocomplete.render_item = function(list, item) {
   }
 
   if (item.post_count !== undefined) {
-    var count;
-    if (item.post_count >= 1000) {
-      count = Math.floor(item.post_count / 1000) + "k";
-    } else {
-      count = item.post_count;
+    var count = item.post_count;
+
+    if (count >= 1000) {
+      count = Math.floor(count / 1000) + "k";
     }
+
     var $post_count = $("<span/>").addClass("post-count").css("float", "right").text(count);
     $link.append($post_count);
   }
@@ -440,7 +439,7 @@ Autocomplete.user_source = function(term, resp, metatag) {
     return window.Danbooru.Autocomplete.user_source(term, resp, metatag);
   }
 
-  $.ajax({
+  return $.ajax({
     url: "/users.json",
     data: {
       "search[order]": "post_upload_count",
@@ -450,8 +449,8 @@ Autocomplete.user_source = function(term, resp, metatag) {
     },
     method: "get",
     success: function(data) {
-      var prefix;
-      var display_name;
+      var prefix = "";
+      var display_name = null;
 
       if (metatag === "@") {
         prefix = "@";
@@ -478,7 +477,7 @@ Autocomplete.pool_source = function(term, resp, metatag) {
     return window.Danbooru.Autocomplete.pool_source(term, resp, metatag);
   }
 
-  $.ajax({
+  return $.ajax({
     url: "/pools.json",
     data: {
       "search[order]": "post_count",
@@ -505,7 +504,7 @@ Autocomplete.favorite_group_source = function(term, resp, metatag) {
     return window.Danbooru.Autocomplete.favorite_group_source(term, resp, metatag);
   }
 
-  $.ajax({
+  return $.ajax({
     url: "/favorite_groups.json",
     data: {
       "search[name_matches]": term,
diff --git a/app/javascript/src/javascripts/blacklists.js b/app/javascript/src/javascripts/blacklists.js
index a834e0cdc..9fbd08727 100644
--- a/app/javascript/src/javascripts/blacklists.js
+++ b/app/javascript/src/javascripts/blacklists.js
@@ -112,7 +112,7 @@ Blacklist.apply = function() {
 
   $.each(this.posts(), function(i, post) {
     var post_count = 0;
-    $.each(Blacklist.entries, function(i, entry) {
+    $.each(Blacklist.entries, function(j, entry) {
       if (Blacklist.post_match(post, entry)) {
         entry.hits += 1;
         count += 1;
@@ -192,7 +192,7 @@ Blacklist.initialize_all = function() {
 }
 
 $(document).ready(function() {
-  if ($("#blacklist-box").length == 0) {
+  if ($("#blacklist-box").length === 0) {
     return;
   }
 
diff --git a/app/javascript/src/javascripts/comments.js b/app/javascript/src/javascripts/comments.js
index 5cb4327d7..544eaad91 100644
--- a/app/javascript/src/javascripts/comments.js
+++ b/app/javascript/src/javascripts/comments.js
@@ -39,7 +39,7 @@ Comment.quote = function(e) {
       var $link = $(e.target);
       var $div = $link.closest("div.comments-for-post").find(".new-comment");
       var $textarea = $div.find("textarea");
-      var msg = data["quoted_response"];
+      var msg = data.quoted_response;
       if ($textarea.val().length > 0) {
         msg = $textarea.val() + "\n\n" + msg;
       }
diff --git a/app/javascript/src/javascripts/common.js b/app/javascript/src/javascripts/common.js
index 38c8dc252..c6428f0e4 100644
--- a/app/javascript/src/javascripts/common.js
+++ b/app/javascript/src/javascripts/common.js
@@ -45,6 +45,6 @@ $(function() {
   });
 });
 
-global.submitInvisibleRecaptchaForm = function () {
+window.submitInvisibleRecaptchaForm = function () {
   document.getElementById("signup-form").submit();
 }
diff --git a/app/javascript/src/javascripts/cookie.js b/app/javascript/src/javascripts/cookie.js
index 3018d4112..20a5e4b0b 100644
--- a/app/javascript/src/javascripts/cookie.js
+++ b/app/javascript/src/javascripts/cookie.js
@@ -31,11 +31,11 @@ Cookie.raw_get = function(name) {
   for (var i = 0; i < ca.length; ++i) {
     var c = ca[i];
 
-    while (c.charAt(0) == " ") {
+    while (c.charAt(0) === " ") {
       c = c.substring(1, c.length);
     }
 
-    if (c.indexOf(nameEq) == 0) {
+    if (c.indexOf(nameEq) === 0) {
       return c.substring(nameEq.length, c.length);
     }
   }
@@ -56,9 +56,9 @@ Cookie.unescape = function(val) {
 }
 
 Cookie.initialize = function() {
-	if (this.get("hide-upgrade-account") != "1") {
-	  $("#upgrade-account").show();
-	}
+  if (this.get("hide-upgrade-account") !== "1") {
+    $("#upgrade-account").show();
+  }
 }
 
 $(function() {
diff --git a/app/javascript/src/javascripts/favorite_groups.js b/app/javascript/src/javascripts/favorite_groups.js
index 16c0b06ee..5445ed1e8 100644
--- a/app/javascript/src/javascripts/favorite_groups.js
+++ b/app/javascript/src/javascripts/favorite_groups.js
@@ -21,7 +21,7 @@ FavoriteGroup.initialize_add_to_favgroup_dialog = function() {
   });
 
   var open_favgroup_dialog = function(e) {
-    if (Utility.meta("current-user-id") == "") { // anonymous
+    if (Utility.meta("current-user-id") === "") { // anonymous
       return;
     }
 
diff --git a/app/javascript/src/javascripts/favorites.js b/app/javascript/src/javascripts/favorites.js
index 96f23d8eb..ef6d2d44a 100644
--- a/app/javascript/src/javascripts/favorites.js
+++ b/app/javascript/src/javascripts/favorites.js
@@ -11,14 +11,14 @@ Favorite.initialize_all = function() {
 
 Favorite.hide_or_show_add_to_favorites_link = function() {
   var current_user_id = Utility.meta("current-user-id");
-  if (current_user_id == "") {
+  if (current_user_id === "") {
     $("#add-to-favorites").hide();
     $("#remove-from-favorites").hide();
     $("#add-fav-button").hide();
     $("#remove-fav-button").hide();
     return;
   }
-  if ($("#image-container").length && $("#image-container").data("is-favorited") == true) {
+  if ($("#image-container").length && $("#image-container").data("is-favorited") === true) {
     $("#add-to-favorites").hide();
     $("#add-fav-button").hide();
   } else {
diff --git a/app/javascript/src/javascripts/forum_posts.js b/app/javascript/src/javascripts/forum_posts.js
index f33b75aed..ec855934d 100644
--- a/app/javascript/src/javascripts/forum_posts.js
+++ b/app/javascript/src/javascripts/forum_posts.js
@@ -3,7 +3,7 @@ import Utility from './utility'
 let ForumPost = {};
 
 ForumPost.initialize_all = function() {
-  if ($("#c-forum-topics #a-show,#c-forum-posts #a-show").length) {;
+  if ($("#c-forum-topics #a-show,#c-forum-posts #a-show").length) {
     this.initialize_edit_links();
 
     Utility.keydown("e", "edit", function(e) {
@@ -44,4 +44,4 @@ $(document).ready(function() {
   ForumPost.initialize_all();
 });
 
-export default ForumPost
\ No newline at end of file
+export default ForumPost
diff --git a/app/javascript/src/javascripts/janitor_trials.js b/app/javascript/src/javascripts/janitor_trials.js
index 1208dc3df..96186ecc0 100644
--- a/app/javascript/src/javascripts/janitor_trials.js
+++ b/app/javascript/src/javascripts/janitor_trials.js
@@ -26,4 +26,4 @@ $(document).ready(function() {
   JanitorTrials.initialize_all();
 });
 
-export default JanitorTrials
\ No newline at end of file
+export default JanitorTrials
diff --git a/app/javascript/src/javascripts/mod_queue.js b/app/javascript/src/javascripts/mod_queue.js
index ad3bf6b37..3752b806c 100644
--- a/app/javascript/src/javascripts/mod_queue.js
+++ b/app/javascript/src/javascripts/mod_queue.js
@@ -66,4 +66,4 @@ $(function() {
   }
 });
 
-export default ModQueue
\ No newline at end of file
+export default ModQueue
diff --git a/app/javascript/src/javascripts/news_updates.js b/app/javascript/src/javascripts/news_updates.js
index e601a43b4..950db3684 100644
--- a/app/javascript/src/javascripts/news_updates.js
+++ b/app/javascript/src/javascripts/news_updates.js
@@ -5,7 +5,7 @@ let NewsUpdate = {};
 NewsUpdate.initialize = function() {
   var key = $("#news-updates").data("id");
 
-  if (Cookie.get("news-ticker") == key) {
+  if (Cookie.get("news-ticker") === key) {
     $("#news-updates").hide();
   } else {
     $("#news-updates").show();
@@ -27,4 +27,4 @@ $(function() {
   NewsUpdate.initialize();
 });
 
-export default NewsUpdate
\ No newline at end of file
+export default NewsUpdate
diff --git a/app/javascript/src/javascripts/notes.js b/app/javascript/src/javascripts/notes.js
index 3a2d5b190..f4ce1d95d 100644
--- a/app/javascript/src/javascripts/notes.js
+++ b/app/javascript/src/javascripts/notes.js
@@ -113,18 +113,18 @@ let Note = {
             return;
           }
 
+          var $this = $(this);
           var $note_box_inner = $(e.currentTarget);
+
           if (e.type === "mouseover") {
             Note.Body.show($note_box_inner.data("id"));
             if (Note.editing) {
-              var $this = $(this);
               $this.resizable("enable");
               $this.draggable("enable");
             }
           } else if (e.type === "mouseout") {
             Note.Body.hide($note_box_inner.data("id"));
             if (Note.editing) {
-              var $this = $(this);
               $this.resizable("disable");
               $this.draggable("disable");
             }
@@ -191,7 +191,7 @@ let Note = {
         return;
       }
       // Hide notes while rescaling, to prevent unnecessary reflowing
-      var was_visible = container.style.display != 'none';
+      var was_visible = container.style.display !== 'none';
       if (was_visible) {
         container.style.display = 'none';
       }
@@ -239,14 +239,6 @@ let Note = {
       var $image = $("#image");
       var doc_width = $image.offset().left + $image.width();
 
-      /*while ($note_body[0].clientHeight < $note_body[0].scrollHeight) {
-        $note_body.css({height: $note_body.height() + 5});
-      }
-
-      while ($note_body[0].clientWidth < $note_body[0].scrollWidth) {
-        $note_body.css({width: $note_body.width() + 5});
-      }*/
-
       if ($note_body.offset().left + $note_body.width() > doc_width) {
         $note_body.css({
           left: $note_body.position().left - 10 - ($note_body.offset().left + $note_body.width() - doc_width)
@@ -286,10 +278,13 @@ let Note = {
       var golden_ratio = 1.6180339887;
       var last = 0;
       var x = 0;
+      var lo = 0;
+      var hi = 0;
 
       if ((w / h) < golden_ratio) {
-        var lo = 140;
-        var hi = 400;
+        lo = 140;
+        hi = 400;
+
         do {
           last = w;
           x = (lo + hi) / 2;
@@ -304,8 +299,8 @@ let Note = {
           }
         } while ((lo < hi) && (w > last));
       } else if ($note_body[0].scrollWidth <= $note_body.width()) {
-        var lo = 20;
-        var hi = w;
+        lo = 20;
+        hi = w;
 
         do {
           x = (lo + hi) / 2;
@@ -466,14 +461,16 @@ let Note = {
     },
 
     success_handler: function(data, status, xhr) {
+      var $note_box = null;
+
       if (data.html_id) { // new note
         var $note_body = Note.Body.find(data.html_id);
-        var $note_box = Note.Box.find(data.html_id);
+        $note_box = Note.Box.find(data.html_id);
         $note_body.data("id", String(data.id)).attr("data-id", data.id);
         $note_box.data("id", String(data.id)).attr("data-id", data.id);
         $note_box.find(".note-box-inner-border").removeClass("unsaved");
       } else {
-        var $note_box = Note.Box.find(data.id);
+        $note_box = Note.Box.find(data.id);
         $note_box.find(".note-box-inner-border").removeClass("unsaved");
       }
     },
@@ -574,7 +571,7 @@ let Note = {
     start: function(e) {
       e.preventDefault();
 
-      if (Utility.meta("current-user-id") == "") {
+      if (Utility.meta("current-user-id") === "") {
         Utility.notice("You must be logged in to edit notes");
         return;
       }
@@ -654,7 +651,7 @@ let Note = {
         var offset = $image.offset();
         var limitX1 = $image.width() - Note.TranslationMode.Drag.dragStartX + offset.left - 1;
         var limitX2 = offset.left - Note.TranslationMode.Drag.dragStartX;
-        var limitY1 = $image.height()- Note.TranslationMode.Drag.dragStartY + offset.top - 1;
+        var limitY1 = $image.height() - Note.TranslationMode.Drag.dragStartY + offset.top - 1;
         var limitY2 = offset.top - Note.TranslationMode.Drag.dragStartY;
 
         if (Note.TranslationMode.Drag.dragDistanceX > limitX1) {
@@ -709,8 +706,8 @@ let Note = {
         $(window).off("mousemove");
 
         if (Note.TranslationMode.Drag.dragging) {
-          $('#note-preview').css({display:'none'});
-          Note.TranslationMode.create_note(e, Note.TranslationMode.Drag.x, Note.TranslationMode.Drag.y, Note.TranslationMode.Drag.w-1, Note.TranslationMode.Drag.h-1);
+          $('#note-preview').css({ display: 'none' });
+          Note.TranslationMode.create_note(e, Note.TranslationMode.Drag.x, Note.TranslationMode.Drag.y, Note.TranslationMode.Drag.w - 1, Note.TranslationMode.Drag.h - 1);
           Note.TranslationMode.Drag.dragging = false; /* border of the note is pixel-perfect on the preview border */
         } else { /* no dragging -> toggle display of notes */
           Note.Box.toggle_all();
@@ -796,7 +793,7 @@ let Note = {
   },
 
   initialize_all: function() {
-    if ($("#c-posts #a-show #image").length == 0 || $("video#image").length) {
+    if ($("#c-posts #a-show #image").length === 0 || $("video#image").length) {
       return;
     }
 
@@ -809,7 +806,7 @@ let Note = {
   },
 
   initialize_shortcuts: function() {
-    if ($("#note-locked-notice").length == 0) {
+    if ($("#note-locked-notice").length === 0) {
       $("#translate").click(Note.TranslationMode.toggle);
       Utility.keydown("n", "translation_mode", Note.TranslationMode.toggle);
     }
diff --git a/app/javascript/src/javascripts/pools.js b/app/javascript/src/javascripts/pools.js
index 521682b9a..67fe3986a 100644
--- a/app/javascript/src/javascripts/pools.js
+++ b/app/javascript/src/javascripts/pools.js
@@ -52,7 +52,7 @@ Pool.initialize_simple_edit = function() {
     $.ajax({
       type: "put",
       url: e.target.action,
-      data: $("#sortable").sortable("serialize") + "&" +  $(e.target).serialize()
+      data: $("#sortable").sortable("serialize") + "&" + $(e.target).serialize()
     });
     e.preventDefault();
   });
@@ -62,4 +62,4 @@ $(document).ready(function() {
   Pool.initialize_all();
 });
 
-export default Pool
\ No newline at end of file
+export default Pool
diff --git a/app/javascript/src/javascripts/post_mode_menu.js b/app/javascript/src/javascripts/post_mode_menu.js
index 22501f230..85b6c8c4f 100644
--- a/app/javascript/src/javascripts/post_mode_menu.js
+++ b/app/javascript/src/javascripts/post_mode_menu.js
@@ -22,20 +22,19 @@ PostModeMenu.initialize_shortcuts = function() {
 }
 
 PostModeMenu.show_notice = function(i) {
-  Utility.notice("Switched to tag script #" + i + ". To switch tag scripts, use the number keys.");    
+  Utility.notice("Switched to tag script #" + i + ". To switch tag scripts, use the number keys.");
 }
 
 PostModeMenu.change_tag_script = function(e) {
   if ($("#mode-box select").val() === "tag-script") {
     var old_tag_script_id = Cookie.get("current_tag_script_id") || "1";
-    var old_tag_script = $("#tag-script-field").val();
-    
+
     var new_tag_script_id = String.fromCharCode(e.which);
     var new_tag_script = Cookie.get("tag-script-" + new_tag_script_id);
-  
+
     $("#tag-script-field").val(new_tag_script);
     Cookie.put("current_tag_script_id", new_tag_script_id);
-    if (old_tag_script_id != new_tag_script_id) {
+    if (old_tag_script_id !== new_tag_script_id) {
       PostModeMenu.show_notice(new_tag_script_id);
     }
 
@@ -145,7 +144,7 @@ PostModeMenu.open_edit = function(post_id) {
   $("#post_tag_string").val($post.data("tags") + " ").focus().selectEnd();
 
   /* Set height of tag edit box to fit content. */
-  $("#post_tag_string").height(80);  // min height: 80px.
+  $("#post_tag_string").height(80); // min height: 80px.
   var padding = $("#post_tag_string").innerHeight() - $("#post_tag_string").height();
   var height = $("#post_tag_string").prop("scrollHeight") - padding;
   $("#post_tag_string").height(height);
diff --git a/app/javascript/src/javascripts/post_popular.js b/app/javascript/src/javascripts/post_popular.js
index 3225195f4..a783adb3b 100644
--- a/app/javascript/src/javascripts/post_popular.js
+++ b/app/javascript/src/javascripts/post_popular.js
@@ -35,4 +35,4 @@ $(document).ready(function() {
   PostPopular.initialize_all();
 });
 
-export default PostPopular
\ No newline at end of file
+export default PostPopular
diff --git a/app/javascript/src/javascripts/post_tooltips.js.erb b/app/javascript/src/javascripts/post_tooltips.js.erb
index 513d75085..01da70720 100644
--- a/app/javascript/src/javascripts/post_tooltips.js.erb
+++ b/app/javascript/src/javascripts/post_tooltips.js.erb
@@ -133,4 +133,4 @@ PostTooltip.on_disable_tooltips = function (event) {
 
 $(document).ready(PostTooltip.initialize);
 
-export default PostTooltip
\ No newline at end of file
+export default PostTooltip
diff --git a/app/javascript/src/javascripts/posts.js.erb b/app/javascript/src/javascripts/posts.js.erb
index 3c506747a..8c8f409f8 100644
--- a/app/javascript/src/javascripts/posts.js.erb
+++ b/app/javascript/src/javascripts/posts.js.erb
@@ -1,3 +1,5 @@
+/* global addthis */
+
 import Utility from './utility'
 import Hammer from 'hammerjs'
 import RelatedTag from './related_tag.js.erb'
@@ -79,7 +81,7 @@ Post.initialize_gestures = function() {
   }
 }
 
-Post.initialize_edit_dialog = function(e) {
+Post.initialize_edit_dialog = function() {
   $("#open-edit-dialog").button().show().click(function(e) {
     $(window).scrollTop($("#image").offset().top);
     Post.open_edit_dialog();
@@ -104,11 +106,11 @@ Post.open_edit_dialog = function() {
   dialog.dialog({
     title: "Edit tags",
     width: $(window).width() * 0.6,
-      position: {
-        my: "right",
-        at: "right-20",
-        of: window
-      },
+    position: {
+      my: "right",
+      at: "right-20",
+      of: window
+    },
     drag: function(e, ui) {
       if (Utility.meta("enable-auto-complete") === "true") {
         $tag_string.data("uiAutocomplete").close();
@@ -128,15 +130,15 @@ Post.open_edit_dialog = function() {
     if (dialog_widget.css("position") === "absolute") {
       pos.left -= $(window).scrollLeft();
       pos.top -= $(window).scrollTop();
-      dialog_widget.offset(pos).css({position:"fixed"});
-      dialog.dialog("option", "resize", function() { dialog_widget.css({position:"fixed"}); });
+      dialog_widget.offset(pos).css({ position: "fixed" });
+      dialog.dialog("option", "resize", function() { dialog_widget.css({ position: "fixed" }); });
 
       pin_button.button("option", "icons", {primary: "ui-icon-pin-s"});
     } else {
       pos.left += $(window).scrollLeft();
       pos.top += $(window).scrollTop();
-      dialog_widget.offset(pos).css({position:"absolute"});
-      dialog.dialog("option", "resize", function() {});
+      dialog_widget.offset(pos).css({ position: "absolute" });
+      dialog.dialog("option", "resize", function() { /* do nothing */ });
 
       pin_button.button("option", "icons", {primary: "ui-icon-pin-w"});
     }
@@ -144,8 +146,7 @@ Post.open_edit_dialog = function() {
 
   dialog.parent().mouseout(function(e) {
     dialog.parent().css({"opacity": 0.6, "transition": "opacity .2s ease"});
-  })
-  .mouseover(function(e) {
+  }).mouseover(function(e) {
     dialog.parent().css({"opacity": 1});
   });
 
@@ -182,15 +183,17 @@ Post.swipe_prev = function(e) {
 }
 
 Post.nav_prev = function(e) {
+  var href = "";
+
   if ($("#search-seq-nav").length) {
-    var href = $("#search-seq-nav a[rel~=prev]").attr("href");
+    href = $("#search-seq-nav a[rel~=prev]").attr("href");
     if (href) {
       location.href = href;
     }
   } else if ($(".paginator a[rel~=prev]").length) {
     location.href = $("a[rel~=prev]").attr("href");
   } else {
-    var href = $("#pool-nav a.active[rel~=prev], #favgroup-nav a.active[rel~=prev]").attr("href");
+    href = $("#pool-nav a.active[rel~=prev], #favgroup-nav a.active[rel~=prev]").attr("href");
     if (href) {
       location.href = href;
     }
@@ -200,13 +203,15 @@ Post.nav_prev = function(e) {
 }
 
 Post.nav_next = function(e) {
+  var href = "";
+
   if ($("#search-seq-nav").length) {
-    var href = $("#search-seq-nav a[rel~=next]").attr("href");
+    href = $("#search-seq-nav a[rel~=next]").attr("href");
     location.href = href;
   } else if ($(".paginator a[rel~=next]").length) {
     location.href = $(".paginator a[rel~=next]").attr("href");
   } else {
-    var href = $("#pool-nav a.active[rel~=next], #favgroup-nav a.active[rel~=next]").attr("href");
+    href = $("#pool-nav a.active[rel~=next], #favgroup-nav a.active[rel~=next]").attr("href");
     if (href) {
       location.href = href;
     }
@@ -301,8 +306,7 @@ Post.toggle_relationship_preview = function(preview, preview_link) {
   if (preview.is(":visible")) {
     preview_link.html("&laquo; hide");
     Cookie.put("show-relationship-previews", "1");
-  }
-  else {
+  } else {
     preview_link.html("show &raquo;");
     Cookie.put("show-relationship-previews", "0");
   }
@@ -343,7 +347,7 @@ Post.expand_image = function(e) {
   $image.attr("src", $link.attr("href"));
   $image.css("opacity", "0.25");
   $image.width($image.data("original-width"));
-  $image.height($image.data("original-height"));        
+  $image.height($image.data("original-height"));
   $image.on("load", function() {
     $image.css("opacity", "1");
     $notice.hide();
@@ -384,14 +388,16 @@ Post.initialize_post_image_resize_links = function() {
 }
 
 Post.resize_image_to_window = function($img) {
+  var sidebar_width = 0;
+  var client_width = 0;
+
   if (($img.data("scale-factor") === 1) || ($img.data("scale-factor") === undefined)) {
     if ($(window).width() > 660) {
-      var sidebar_width = $("#sidebar").width() || 0;
-      var client_width = $(window).width() - sidebar_width - 75;
+      sidebar_width = $("#sidebar").width() || 0;
+      client_width = $(window).width() - sidebar_width - 75;
     } else {
-      var client_width = $(window).width() - 2;
+      client_width = $(window).width() - 2;
     }
-    var client_height = $(window).height();
 
     if ($img.width() > client_width) {
       var ratio = client_width / $img.data("original-width");
@@ -473,7 +479,7 @@ Post.initialize_post_sections = function() {
       $("#share").show();
       addthis.init();
       $("#recommended").hide();
-    } 
+    }
 
     $("#post-sections li").removeClass("active");
     $(e.target).parent("li").addClass("active");
@@ -525,7 +531,7 @@ Post.vote = function(score, id) {
   $(window).trigger("danbooru:notice", "Voting...");
 
   $.post("/posts/" + id + "/votes.js", {
-     score: score
+    score: score
   });
 }
 
@@ -583,12 +589,10 @@ Post.approve = function(post_id) {
 Post.favorite = function (e) {
   if ($("#add-to-favorites").is(":visible")) {
     $("#add-to-favorites")[0].click();
+  } else if (Utility.meta("current-user-id") === "") {
+    $(window).trigger("danbooru:notice", "You must be logged in to favorite posts");
   } else {
-    if (Utility.meta("current-user-id") == "") {
-      $(window).trigger("danbooru:notice", "You must be logged in to favorite posts");
-    } else {
-      $(window).trigger("danbooru:notice", "You have already favorited this post");
-    }
+    $(window).trigger("danbooru:notice", "You have already favorited this post");
   }
 };
 
@@ -690,4 +694,4 @@ $(document).ready(function() {
   Post.initialize_all();
 });
 
-export default Post
\ No newline at end of file
+export default Post
diff --git a/app/javascript/src/javascripts/related_tag.js.erb b/app/javascript/src/javascripts/related_tag.js.erb
index d627881a3..af37bd629 100644
--- a/app/javascript/src/javascripts/related_tag.js.erb
+++ b/app/javascript/src/javascripts/related_tag.js.erb
@@ -15,18 +15,14 @@ RelatedTag.initialize_all = function() {
 RelatedTag.initialize_buttons = function() {
   this.common_bind("#related-tags-button", "");
   <% TagCategory.related_button_list.each do |category| %>
-    RelatedTag.common_bind("#related-<%= category %>-button", "<%= category %>");
+    RelatedTag.common_bind("#related-<%= category %>-button", "<%= category %>"); // eslint-disable-line indent
   <% end %>
   $("#find-artist-button").click(RelatedTag.find_artist);
 }
 
 RelatedTag.tags_include = function(name) {
   var current = $("#upload_tag_string,#post_tag_string").val().toLowerCase().match(/\S+/g) || [];
-  if ($.inArray(name.toLowerCase(), current) > -1) {
-    return true;
-  } else {
-    return false;
-  }
+  return $.inArray(name.toLowerCase(), current) > -1;
 }
 
 RelatedTag.common_bind = function(button_name, category) {
@@ -89,7 +85,7 @@ RelatedTag.current_tag = function() {
   }
 
   b++;
-	return string.slice(a, b);
+  return string.slice(a, b);
 }
 
 RelatedTag.process_response = function(data) {
@@ -130,7 +126,7 @@ RelatedTag.build_all = function() {
   if (wiki_page_tags.length) {
     $dest.append(RelatedTag.build_html("wiki:" + query, wiki_page_tags, "wiki"));
   }
-  $.each(other_wikis, function(i,wiki) {
+  $.each(other_wikis, function(i, wiki) {
     $dest.append(RelatedTag.build_html("wiki:" + wiki.title, wiki.wiki_page_tags, "otherwiki" + i.toString()));
   });
   if (RelatedTag.recent_artists) {
@@ -156,7 +152,7 @@ RelatedTag.build_all = function() {
         tags.push([artist.name, 1]);
       });
     }
-   $dest.append(RelatedTag.build_html("artist", tags, "artist", true));
+    $dest.append(RelatedTag.build_html("artist", tags, "artist", true));
   }
 }
 
@@ -231,9 +227,10 @@ RelatedTag.build_html = function(query, related_tags, name, is_wide_column) {
       );
     } else {
       var text = tag[0];
+      var desc = "";
       if (text.match(/^ -http/)) {
         text = text.substring(1, 1000);
-        var desc = text.replace(/^-https?:\/\//, "");
+        desc = text.replace(/^-https?:\/\//, "");
         if (desc.length > 30) {
           desc = desc.substring(0, 30) + "...";
         }
@@ -244,7 +241,7 @@ RelatedTag.build_html = function(query, related_tags, name, is_wide_column) {
         );
       } else if (text.match(/^ http/)) {
         text = text.substring(1, 1000);
-        var desc = text.replace(/^https?:\/\//, "");
+        desc = text.replace(/^https?:\/\//, "");
         if (desc.length > 30) {
           desc = desc.substring(0, 30) + "...";
         }
@@ -284,7 +281,7 @@ RelatedTag.toggle_tag = function(e) {
     RelatedTag.process_artist(RelatedTag.recent_artist);
   }
 
-  //The timeout is needed on Chrome since it will clobber the field attribute otherwise
+  // The timeout is needed on Chrome since it will clobber the field attribute otherwise
   setTimeout(function () { $field.prop('selectionStart', $field.val().length);}, 100);
   e.preventDefault();
 }
@@ -295,7 +292,7 @@ RelatedTag.find_artist = function(e) {
   var referer_url = $("#upload_referer_url");
   $.get("/artists/finder.json", {"url": url.val(), "referer_url": referer_url.val()}, RelatedTag.process_artist);
   if (e) {
-    e.preventDefault();      
+    e.preventDefault();
   }
 }
 
@@ -328,12 +325,12 @@ RelatedTag.hide = function() {
 RelatedTag.disable_artist_url = function(e) {
   var url = e.currentTarget.href;
   $.each(RelatedTag.recent_artists[0].sorted_urls, function(k, v) {
-    if (v["normalized_url"] === url || v["url"] === url) {
+    if (v.normalized_url === url || v.url === url) {
       if (!confirm("This will mark the URL as inactive. Continue?")) {
         return;
       }
-      
-      $.ajax("/artist_urls/" + v["id"], {
+
+      $.ajax("/artist_urls/" + v.id, {
         method: "PUT",
         data: {
           artist_url: {
diff --git a/app/javascript/src/javascripts/saved_searches.js b/app/javascript/src/javascripts/saved_searches.js
index dc6d38b5f..4f0e0bc48 100644
--- a/app/javascript/src/javascripts/saved_searches.js
+++ b/app/javascript/src/javascripts/saved_searches.js
@@ -17,4 +17,4 @@ SavedSearch.labels = function(term) {
 
 $(SavedSearch.initialize_all);
 
-export default SavedSearch
\ No newline at end of file
+export default SavedSearch
diff --git a/app/javascript/src/javascripts/shortcuts.js b/app/javascript/src/javascripts/shortcuts.js
index 9b0363ce6..5cdc09666 100644
--- a/app/javascript/src/javascripts/shortcuts.js
+++ b/app/javascript/src/javascripts/shortcuts.js
@@ -14,7 +14,7 @@ Shortcuts.initialize = function() {
 
   if ($("#image").length) { // post page or bookmarklet upload page
     Utility.keydown("shift+e", "edit_dialog", function(e) {
-      if (Utility.meta("current-user-id") == "") { // anonymous
+      if (Utility.meta("current-user-id") === "") { // anonymous
         return;
       }
 
@@ -56,4 +56,4 @@ $(document).ready(function() {
   Shortcuts.initialize();
 });
 
-export default Shortcuts
\ No newline at end of file
+export default Shortcuts
diff --git a/app/javascript/src/javascripts/tag_script.js b/app/javascript/src/javascripts/tag_script.js
index ba20ee1a7..4ecbf5ba1 100644
--- a/app/javascript/src/javascripts/tag_script.js
+++ b/app/javascript/src/javascripts/tag_script.js
@@ -16,10 +16,8 @@ TagScript.test = function(tags, predicate) {
       if ($.inArray(x.substr(1, 100), tags)) {
         is_true = false;
       }
-    } else {
-      if (!$.inArray(x, tags)) {
-        is_true = false;
-      }
+    } else if (!$.inArray(x, tags)) {
+      is_true = false;
     }
   });
 
@@ -57,4 +55,4 @@ TagScript.run = function(post_id, tag_script) {
   Post.update(post_id, {"post[old_tag_string]": old_tags, "post[tag_string]": $post.data("tags")});
 }
 
-export default TagScript
\ No newline at end of file
+export default TagScript
diff --git a/app/javascript/src/javascripts/ugoira.js b/app/javascript/src/javascripts/ugoira.js
index 8c8a0af65..6fee99ef3 100644
--- a/app/javascript/src/javascripts/ugoira.js
+++ b/app/javascript/src/javascripts/ugoira.js
@@ -50,7 +50,7 @@ Ugoira.create_player = (mime_type, frames, file_url) => {
 
   $("#seek-slider").slider({
     min: 0,
-    max: Ugoira.player._frameCount-1,
+    max: Ugoira.player._frameCount - 1,
     start: (event, ui) => {
       // Need to pause while slider is being dragged or playback speed will bug out
       Ugoira.player.pause();
diff --git a/app/javascript/src/javascripts/uploads.js b/app/javascript/src/javascripts/uploads.js
index 51e491a0e..99ef33de8 100644
--- a/app/javascript/src/javascripts/uploads.js
+++ b/app/javascript/src/javascripts/uploads.js
@@ -1,6 +1,5 @@
 import Utility from './utility'
 import Post from './posts.js.erb'
-import Artist from './artists'
 import RelatedTag from './related_tag.js.erb'
 
 let Upload = {};
@@ -45,8 +44,8 @@ Upload.initialize_submit = function() {
       error_messages.push("Must specify a rating");
     }
     if (error_messages.length === 0) {
-      $("#submit-button").prop("disabled","true");
-      $("#submit-button").prop("value","Submitting...");
+      $("#submit-button").prop("disabled", "true");
+      $("#submit-button").prop("value", "Submitting...");
       $("#client-errors").hide();
     } else {
       $("#client-errors").html("<strong>Error</strong>: " + error_messages.join(", "));
@@ -112,7 +111,7 @@ Upload.fetch_source_data = function(url, referer_url) {
   return $.getJSON("/source.json", { url: url, ref: referer_url })
     .then(Upload.fill_source_info)
     .catch(function(data) {
-      $("#source-info span#loading-data").html("Error: " + data.responseJSON["message"])
+      $("#source-info span#loading-data").html("Error: " + data.responseJSON.message)
     });
 }
 
diff --git a/app/javascript/src/javascripts/utility.js b/app/javascript/src/javascripts/utility.js
index b5c041877..d287ac4d6 100644
--- a/app/javascript/src/javascripts/utility.js
+++ b/app/javascript/src/javascripts/utility.js
@@ -22,7 +22,7 @@ Utility.scroll_to = function(element) {
   }
 
   var top = null;
-  if (typeof(element) === "number") {
+  if (typeof element === "number") {
     top = element;
   } else {
     top = element.offset().top - 10;
@@ -76,8 +76,7 @@ Utility.intersect = function(a, b) {
   a = a.slice(0).sort();
   b = b.slice(0).sort();
   var result = [];
-  while (a.length > 0 && b.length > 0)
-  {
+  while (a.length > 0 && b.length > 0) {
     if (a[0] < b[0]) {
       a.shift();
     } else if (a[0] > b[0]) {
@@ -150,7 +149,7 @@ $.fn.selectRange = function(start, end) {
   });
 };
 
-$.fn.selectEnd = function(){
+$.fn.selectEnd = function() {
   if (this.length) {
     this.selectRange(this.val().length, this.val().length);
   }