diff --git a/.eslintrc.js b/.eslintrc.js
index f36320e75..46806b19b 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -1,7 +1,5 @@
 'use strict';
 
-const os = require('os');
-
 module.exports = {
 	"root": true,
 	"parserOptions": {
diff --git a/js/client-battle-tooltips.js b/js/client-battle-tooltips.js
index 3ee2c8e5a..ec909145c 100644
--- a/js/client-battle-tooltips.js
+++ b/js/client-battle-tooltips.js
@@ -441,8 +441,8 @@ var BattleTooltips = (function () {
 				}
 				text += '</p>';
 			} else if (pokemonData.item) {
-				item = Tools.getItem(pokemonData.item).name;
-				text += '<p>Item: ' + item + '</p>';
+				var itemName = Tools.getItem(pokemonData.item).name;
+				text += '<p>Item: ' + itemName + '</p>';
 			}
 			text += '<p>' + pokemonData.stats['atk'] + '&nbsp;Atk /&nbsp;' + pokemonData.stats['def'] + '&nbsp;Def /&nbsp;' + pokemonData.stats['spa'];
 			if (this.battle.gen === 1) {
@@ -868,28 +868,20 @@ var BattleTooltips = (function () {
 		}
 		// Weather and pseudo-weather type changes.
 		if (move.id === 'weatherball' && this.battle.weather) {
-			var noWeatherAbility = false;
-			// Check if your side has an anti weather ability to skip this.
-			if (!noWeatherAbility) {
-				for (var i = 0; i < this.battle.mySide.active.length; i++) {
-					if (this.battle.mySide.active[i] && this.battle.mySide.active[i].ability in {'Air Lock': 1, 'Cloud Nine': 1}) {
-						noWeatherAbility = true;
-						break;
-					}
-				}
-			}
-			// If you don't, check if the opponent has it afterwards.
-			if (!noWeatherAbility) {
-				for (var i = 0; i < this.battle.yourSide.active.length; i++) {
-					if (this.battle.yourSide.active[i] && this.battle.yourSide.active[i].ability in {'Air Lock': 1, 'Cloud Nine': 1}) {
-						noWeatherAbility = true;
-						break;
+			var antiWeatherAbility = false;
+			// Check if there's an anti weather ability to skip this.
+			abilitySearch: for (var i = 0; i < this.battle.sides.length; i++) {
+				var side = this.battle.sides[i];
+				for (var j = 0; j < side.active.length; j++) {
+					if (side.active[j] && ['Air Lock', 'Cloud Nine'].includes(side.active[j].ability)) {
+						antiWeatherAbility = true;
+						break abilitySearch;
 					}
 				}
 			}
 
 			// If the weather is indeed active, check it to see what move type weatherball gets.
-			if (!noWeatherAbility) {
+			if (!antiWeatherAbility) {
 				if (this.battle.weather === 'sunnyday' || this.battle.weather === 'desolateland') moveType = 'Fire';
 				if (this.battle.weather === 'raindance' || this.battle.weather === 'primordialsea') moveType = 'Water';
 				if (this.battle.weather === 'sandstorm') moveType = 'Rock';
@@ -989,26 +981,18 @@ var BattleTooltips = (function () {
 			if (move.id in table.overrideBP) basePower = table.overrideBP[move.id];
 		}
 		var basePowerComment = '';
-		var noWeatherAbility = false;
-		// Check if your side has an anti weather ability to skip this.
-		if (!noWeatherAbility) {
-			for (var i = 0; i < this.battle.mySide.active.length; i++) {
-				if (this.battle.mySide.active[i] && this.battle.mySide.active[i].ability in {'Air Lock': 1, 'Cloud Nine': 1}) {
-					noWeatherAbility = true;
-					break;
+		var antiWeatherAbility = false;
+		// Check if there's an anti weather ability to skip this.
+		abilitySearch2: for (var i = 0; i < this.battle.sides.length; i++) {
+			var side = this.battle.sides[i];
+			for (var j = 0; j < side.active.length; j++) {
+				if (side.active[j] && ['Air Lock', 'Cloud Nine'].includes(side.active[j].ability)) {
+					antiWeatherAbility = true;
+					break abilitySearch2;
 				}
 			}
 		}
-		// If you don't, check if the opponent has it afterwards.
-		if (!noWeatherAbility) {
-			for (var i = 0; i < this.battle.yourSide.active.length; i++) {
-				if (this.battle.yourSide.active[i] && this.battle.yourSide.active[i].ability in {'Air Lock': 1, 'Cloud Nine': 1}) {
-					noWeatherAbility = true;
-					break;
-				}
-			}
-		}
-		var thereIsWeather = !!this.battle.weather && !noWeatherAbility;
+		var thereIsWeather = !!this.battle.weather && !antiWeatherAbility;
 		if (move.id === 'acrobatics') {
 			if (!pokemonData.item) {
 				basePower *= 2;
diff --git a/js/client-battle.js b/js/client-battle.js
index 6662fde76..7e63640f9 100644
--- a/js/client-battle.js
+++ b/js/client-battle.js
@@ -323,11 +323,7 @@
 		},
 		controlsShown: false,
 		updateControlsForPlayer: function () {
-			var battle = this.battle;
-
 			this.callbackWaiting = true;
-			var active = this.battle.mySide.active[0];
-			if (!active) active = {};
 
 			var act = '';
 			var switchables = [];
@@ -904,7 +900,6 @@
 				return;
 			}
 			request.requestType = 'move';
-			var notifyObject = null;
 			if (request.forceSwitch) {
 				request.requestType = 'switch';
 			} else if (request.teamPreview) {
@@ -998,7 +993,6 @@
 			e.stopPropagation();
 		},
 		switchSides: function () {
-			var paused = this.battle.paused;
 			this.battle.switchSides();
 		},
 		pause: function () {
@@ -1060,10 +1054,8 @@
 				var isZMove = !!(this.$('input[name=zmove]')[0] || '').checked;
 				var isUltraBurst = !!(this.$('input[name=ultraburst]')[0] || '').checked;
 
-				var move = e.getAttribute('data-move');
 				var target = e.getAttribute('data-target');
 				var choosableTargets = {normal: 1, any: 1, adjacentAlly: 1, adjacentAllyOrSelf: 1, adjacentFoe: 1};
-				var spreadTargets = {allAdjacentFoes: 1, allAdjacent: 1};
 
 				this.choice.choices.push('move ' + pos + (isMega ? ' mega' : '') + (isZMove ? ' zmove' : '') + (isUltraBurst ? ' ultra' : ''));
 				if (myActive.length > 1 && target in choosableTargets) {
diff --git a/js/client-chat-tournament.js b/js/client-chat-tournament.js
index e85cebf66..384987607 100644
--- a/js/client-chat-tournament.js
+++ b/js/client-chat-tournament.js
@@ -804,7 +804,7 @@
 		initialize: function (data) {
 			this.$el.html('<ul class="popupmenu">' + data.users.map(function (user) {
 				var escapedUser = Tools.escapeHTML(user);
-				return '<li><button name="selectUser" value="' + Tools.escapeQuotes(escapedUser) + '"' + (user === data.user ? ' class="sel"' : '') + '>' + escapedUser + '</button></li>';
+				return '<li><button name="selectUser" value="' + escapedUser + '"' + (user === data.user ? ' class="sel"' : '') + '>' + escapedUser + '</button></li>';
 			}).join('') + '</ul>');
 		},
 		selectUser: function (user) {
diff --git a/js/client-chat.js b/js/client-chat.js
index 5f28a439e..b9155ed27 100644
--- a/js/client-chat.js
+++ b/js/client-chat.js
@@ -860,14 +860,13 @@
 			case 'join':
 			case 'j':
 				if (noSpace) return text;
-				var room = toRoomid(target);
 				if (app.rooms[target]) {
 					app.focusRoom(target);
 					return false;
 				}
-				room = toId(target);
-				if (app.rooms[room]) {
-					app.focusRoom(room);
+				var roomid = toId(target);
+				if (app.rooms[roomid]) {
+					app.focusRoom(roomid);
 					return false;
 				}
 				return text; // Send the /join command through to the server.
@@ -1182,7 +1181,7 @@
 			}
 		},
 		addRow: function (line) {
-			var name, name2, room, action, silent, oldid;
+			var name, name2, silent;
 			if (line && typeof line === 'string') {
 				if (line.charAt(0) !== '|') line = '||' + line;
 				var row = line.substr(1).split('|');
@@ -1229,7 +1228,7 @@
 					if (!matches) {
 						return; // bogus room ID could be used to inject JavaScript
 					}
-					var format = Tools.escapeFormat(matches ? matches[1] : '');
+					var format = Tools.escapeFormat(matches[1]);
 
 					if (silent && !Tools.prefs('showbattles')) return;
 
@@ -1621,7 +1620,7 @@
 					return self.comparator(a, b);
 				});
 			}
-			for (var i = 0, len = users.length; i < users.length; i++) {
+			for (var i = 0; i < users.length; i++) {
 				var userid = users[i];
 				buf += this.constructItem(userid);
 			}
diff --git a/js/client-ladder.js b/js/client-ladder.js
index 769d66241..5cd7d4ec3 100644
--- a/js/client-ladder.js
+++ b/js/client-ladder.js
@@ -27,7 +27,6 @@
 			app.send('/leave ' + this.id);
 		},
 		addRow: function (line) {
-			var name, name2, room, action, silent, oldid;
 			if (!line || typeof line !== 'string') return;
 			if (line.charAt(0) !== '|') line = '||' + line;
 			var pipeIndex = line.indexOf('|', 1);
diff --git a/js/client-mainmenu.js b/js/client-mainmenu.js
index 1736e82cd..cf80f4057 100644
--- a/js/client-mainmenu.js
+++ b/js/client-mainmenu.js
@@ -657,7 +657,6 @@
 			if (atLeastOneGen5 && !Tools.loadedSpriteData['bw']) Tools.loadSpriteData('bw');
 		},
 		openChallenge: function (name, $pmWindow) {
-			var userid = toId(name);
 			if (!$pmWindow) $pmWindow = this.openPM(name, true);
 			var $challenge = $pmWindow.find('.challenge');
 			if (!$challenge.length) {
@@ -693,7 +692,6 @@
 		},
 		updateTeams: function () {
 			if (!window.BattleFormats) return;
-			var teams = Storage.teams;
 			var self = this;
 
 			this.$('button[name=team]').each(function (i, el) {
@@ -942,7 +940,6 @@
 			var curSection = '';
 			for (var i in BattleFormats) {
 				var format = BattleFormats[i];
-				var selected = false;
 				if (selectType === 'teambuilder') {
 					if (!format.isTeambuilderFormat) continue;
 				} else {
diff --git a/js/client-teambuilder.js b/js/client-teambuilder.js
index b3c819e57..e0ae11207 100644
--- a/js/client-teambuilder.js
+++ b/js/client-teambuilder.js
@@ -283,6 +283,7 @@
 						buf += '<div class="folder"><h3>Gen ' + gen + '</h3></div>';
 					}
 				}
+				var formatName;
 				if (gen === '/') {
 					formatName = format.slice(1);
 					format = formatName + '/';
@@ -295,7 +296,7 @@
 					buf += '<div class="folder' + (this.curFolder === format ? ' cur"><div class="folderhack3"><div class="folderhack1"></div><div class="folderhack2"></div>' : '">') + '<div class="selectFolder" data-value="' + format + '"><i class="fa ' + (this.curFolder === format ? 'fa-folder-open' : 'fa-folder') + (format === '/' ? '-o' : '') + '"></i>' + formatName + '</div></div>' + (this.curFolder === format ? '</div>' : '');
 					continue;
 				}
-				var formatName = format.slice(1);
+				formatName = format.slice(1);
 				if (formatName === '~') formatName = '';
 				format = 'gen' + newGen + formatName;
 				if (format.length === 4) formatName = '(uncategorized)';
@@ -768,7 +769,6 @@
 			e.currentTarget.className = 'team';
 		},
 		dragStartTeam: function (e) {
-			var target = e.currentTarget;
 			var dataTransfer = e.originalEvent.dataTransfer;
 
 			dataTransfer.effectAllowed = 'copyMove';
@@ -836,7 +836,6 @@
 			this.$('.teamlist').css('pointer-events', 'none');
 			$(teamEl).parent().removeClass('dragging');
 
-			var format = this.curFolder;
 			if (app.draggingFolder) {
 				var $folder = $(app.draggingFolder);
 				app.draggingFolder = null;
@@ -848,7 +847,7 @@
 					var count = Number($plusOneFolder.text().substr(1)) + 1;
 					$plusOneFolder.text('+' + count);
 				}
-				format = $folder.data('value');
+				var format = $folder.data('value');
 				if (format.slice(-1) === '/') {
 					team.folder = format.slice(0, -1);
 				} else {
@@ -1873,9 +1872,6 @@
 			this.plus = '';
 			this.minus = '';
 			for (var i in stats) {
-				var width = stats[i] * 200 / 504;
-				if (i == 'hp') width = stats[i] * 200 / 704;
-				if (width > 200) width = 200;
 				var val;
 				if (this.curTeam.gen > 2) {
 					val = '' + (set.evs[i] || '');
@@ -2426,7 +2422,6 @@
 			var val = entry.slice(entry.indexOf("|") + 1);
 			if (this.curChartType === 'move' && e.currentTarget.className === 'cur') {
 				// clicked a move, remove it if we already have it
-				var $emptyEl;
 				var moves = [];
 				for (var i = 1; i <= 4; i++) {
 					var $inputEl = this.$('input[name=move' + i + ']');
@@ -2606,7 +2601,6 @@
 		},
 		chartSet: function (val, selectNext) {
 			var inputName = this.curChartName;
-			var id = toId(val);
 			var input = this.$('input[name=' + inputName + ']');
 			if (this.chartSetCustom(input.val())) return;
 			input.val(val).removeClass('incomplete');
@@ -2770,7 +2764,6 @@
 		setPokemon: function (val, selectNext) {
 			var set = this.curSet;
 			var template = Tools.getTemplate(val);
-			var newPokemon = !set.species;
 			if (!template.exists || set.species === template.species) {
 				if (selectNext) this.$('input[name=item]').select();
 				return;
@@ -3040,7 +3033,6 @@
 			else if (stats.atk > stats.spa && moveCount['Physical'] > 1) offenseBias = 'Physical';
 			else if (moveCount['Special'] > moveCount['Physical']) offenseBias = 'Special';
 			else offenseBias = 'Physical';
-			var offenseStat = stats[offenseBias === 'Special' ? 'spa' : 'atk'];
 
 			if (moveCount['Stall'] + moveCount['Support'] / 2 <= 2 && bulk < 135000 && moveCount[offenseBias] >= 1.5) {
 				if (isFast) {
diff --git a/js/client.js b/js/client.js
index 7b65e1520..402ca600d 100644
--- a/js/client.js
+++ b/js/client.js
@@ -1527,7 +1527,6 @@
 			var leftMin = (this.curRoom.minWidth || this.curRoom.bestWidth);
 			var leftMinMain = (this.curRoom.minMainWidth || leftMin);
 			var rightMin = (this.sideRoom.minWidth || this.sideRoom.bestWidth);
-			var rightMinMain = (this.sideRoom.minMainWidth || leftMin);
 			var available = $(window).width();
 			if (this.curRoom.isSideRoom) {
 				// we're trying to focus a side room
diff --git a/js/search.js b/js/search.js
index a8444fc7a..8d4aef539 100644
--- a/js/search.js
+++ b/js/search.js
@@ -897,7 +897,7 @@
 				var abilities = [];
 				if (template.isMega) {
 					if (format === 'almostanyability') abilitySet.unshift(['html', '<p>Will be <strong>' + Tools.escapeHTML(template.abilities['0']) + '</strong> after Mega Evolving.</p>']);
-					template = Tools.getTemplate(template.baseSpecies);
+					// template is unused after this, so no need to replace
 				}
 				for (var i in BattleAbilities) {
 					if (BattleAbilities[i].isNonstandard) continue;
diff --git a/js/storage.js b/js/storage.js
index d2018b60c..70ed04aee 100644
--- a/js/storage.js
+++ b/js/storage.js
@@ -176,7 +176,6 @@ Storage.bg = {
 		var s;
 		var l = (max + min) / 2;
 		if (max === min) {
-			h = s = 0;
 			return '0, 0%';
 		} else {
 			var d = max - min;
@@ -1260,7 +1259,7 @@ Storage.exportTeam = function (team) {
 			}
 			if (defaultIvs && !hpType) {
 				for (var stat in BattleStatNames) {
-					if (curSet.ivs[stat] !== 31 && typeof curSet.ivs[stat] !== undefined) {
+					if (curSet.ivs[stat] !== 31 && curSet.ivs[stat] !== undefined) {
 						defaultIvs = false;
 						break;
 					}
@@ -1282,7 +1281,7 @@ Storage.exportTeam = function (team) {
 		if (!first) {
 			text += "  \n";
 		}
-		if (curSet.moves && curSet.moves) for (var j = 0; j < curSet.moves.length; j++) {
+		if (curSet.moves) for (var j = 0; j < curSet.moves.length; j++) {
 			var move = curSet.moves[j];
 			if (move.substr(0, 13) === 'Hidden Power ') {
 				move = move.substr(0, 13) + '[' + move.substr(13) + ']';
@@ -1506,19 +1505,16 @@ Storage.nwDeleteAllTeams = function (callback) {
 };
 
 Storage.nwDeleteTeamFile = function (filename, callback) {
-	var self = this;
-	var line = filename;
-	if (line.substr(line.length - 4).toLowerCase() === '.txt') {
-		line = line.substr(0, line.length - 4);
-	} else {
+	if (filename.slice(-4).toLowerCase() !== '.txt') {
 		// not a team file
-		self.nwTeamsLeft--;
-		if (!self.nwTeamsLeft) {
+		this.nwTeamsLeft--;
+		if (!this.nwTeamsLeft) {
 			if (callback) callback();
 			Storage.fsReady.load();
 		}
 		return;
 	}
+	var self = this;
 	fs.unlink(this.dir + 'Teams/' + filename, function (err) {
 		var directory = filename.split('/').slice(0, -1).join('/');
 		fs.rmdir(directory, function () {});
@@ -1627,7 +1623,6 @@ Storage.nwStopLoggingChat = function () {
 };
 Storage.nwLogChat = function (roomid, line) {
 	roomid = toRoomid(roomid);
-	var self = this;
 	if (!this.loggingChat) return;
 	var chatLogFdMonth = this.getLogMonth();
 	if (chatLogFdMonth !== this.chatLogFdMonth) {
diff --git a/lib/validate-token.js b/lib/validate-token.js
index ed350bef1..c14ad1993 100644
--- a/lib/validate-token.js
+++ b/lib/validate-token.js
@@ -6,7 +6,6 @@ const CLIENT_ID = '912270888098-jjnre816lsuhc5clj3vbcn4o2q7p4qvk.apps.googleuser
 
 const token = process.argv[2];
 
-var auth = new gal.GoogleAuth();
 var client = new gal.OAuth2Client(CLIENT_ID, '', '');
 client.verifyIdToken({
   idToken: token,
@@ -17,7 +16,7 @@ client.verifyIdToken({
   function(e, login) {
     if (e) return console.log(e);
     var payload = login.getPayload();
-    var userid = payload['sub'];
+    // var userid = payload['sub'];
     console.log(JSON.stringify(payload));
     // If request specified a G Suite domain:
     //var domain = payload['hd'];
diff --git a/src/battle-animations.ts b/src/battle-animations.ts
index 46f816559..ac8a09799 100644
--- a/src/battle-animations.ts
+++ b/src/battle-animations.ts
@@ -320,7 +320,6 @@ class BattleScene {
 
 		left = 210;
 		top = 245;
-		scale = 1;
 		scale = 1.5 - 0.5 * ((loc.z!) / 200);
 		if (scale < .1) scale = .1;
 
diff --git a/src/battle-dex.ts b/src/battle-dex.ts
index 1809de586..dc79e548e 100644
--- a/src/battle-dex.ts
+++ b/src/battle-dex.ts
@@ -415,7 +415,7 @@ const Tools = {
 
 	escapeHTML(str: string, jsEscapeToo?: boolean) {
 		str = getString(str).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
-		if (jsEscapeToo) str = str.replace(/'/g, '\\\'');
+		if (jsEscapeToo) str = str.replace(/\\/g, '\\\\').replace(/'/g, '\\\'');
 		return str;
 	},
 
@@ -428,12 +428,6 @@ const Tools = {
 		return str.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, "\\$&");
 	},
 
-	escapeQuotes(str: string) {
-		str = (str ? '' + str : '');
-		str = str.replace(/'/g, '\\\'');
-		return str;
-	},
-
 	sanitizeHTML: (function () {
 		if (!('html4' in window)) {
 			return function () {
diff --git a/src/battle.ts b/src/battle.ts
index 23975dcc7..df9d910a3 100644
--- a/src/battle.ts
+++ b/src/battle.ts
@@ -250,7 +250,6 @@ class Pokemon {
 		delete this.volatiles[volatile];
 	}
 	addVolatile(volatile: ID, ...args: any[]) {
-		let battle = this.side.battle;
 		if (this.hasVolatile(volatile) && !args.length) return;
 		this.volatiles[volatile] = [volatile, ...args] as EffectState;
 		this.sprite.addEffect(volatile);
@@ -265,7 +264,6 @@ class Pokemon {
 	}
 	addTurnstatus(volatile: ID) {
 		volatile = toId(volatile);
-		let battle = this.side.battle;
 		this.sprite.addEffect(volatile);
 		if (this.hasTurnstatus(volatile)) return;
 		this.turnstatuses[volatile] = [volatile];
@@ -633,7 +631,7 @@ class Side {
 		this.spriteid = spriteid;
 	}
 	setName(name: string, spriteid?: string | number) {
-		if (name) this.name = (name || '');
+		if (name) this.name = name;
 		this.id = toId(this.name);
 		if (spriteid) {
 			this.spriteid = spriteid;
@@ -652,7 +650,6 @@ class Side {
 		return "the opposing team";
 	}
 	addSideCondition(effect: Effect) {
-		let elem, curelem;
 		let condition = effect.id;
 		if (this.sideConditions[condition]) {
 			if (condition === 'spikes' || condition === 'toxicspikes') {
@@ -709,7 +706,6 @@ class Side {
 		this.battle.scene.removeSideCondition(this.n, id);
 	}
 	newPokemon(data: any, replaceSlot = -1) {
-		let pokeobj;
 		let poke = new Pokemon(data, this);
 		if (!poke.ability && poke.baseAbility) poke.ability = poke.baseAbility;
 		poke.reset();
@@ -1306,7 +1302,9 @@ class Battle {
 			if (!this.fastForward) {
 				this.scene.upkeepWeather();
 			}
-			if (newWeather && newWeather.upkeepMessage) this.message('<div><small>' + newWeather.upkeepMessage + '</small></div>');
+			if (newWeather && newWeather.upkeepMessage) {
+				this.message('<div><small>' + newWeather.upkeepMessage + '</small></div>');
+			}
 			return;
 		}
 		if (newWeather) {
@@ -1322,10 +1320,6 @@ class Battle {
 				}
 				this.weatherTimeLeft = (this.gen <= 5 || isExtremeWeather) ? 0 : 8;
 				this.weatherMinTimeLeft = (this.gen <= 5 || isExtremeWeather) ? 0 : 5;
-			} else if (isUpkeep) {
-				this.scene.log('<div><small>' + newWeather.upkeepMessage + '</small></div>');
-				this.weatherTimeLeft = 0;
-				this.weatherMinTimeLeft = 0;
 			} else if (isExtremeWeather) {
 				this.message('<small>' + newWeather.startMessage + '</small>');
 				this.weatherTimeLeft = 0;
@@ -4577,7 +4571,6 @@ class Battle {
 				newSpecies = args[2].substr(0, commaIndex);
 			}
 			let template = Tools.getTemplate(newSpecies);
-			let spriteData = {'shiny': poke.sprite.sp.shiny};
 
 			poke.species = newSpecies;
 			poke.ability = poke.baseAbility = (template.abilities ? template.abilities['0'] : '');
@@ -4890,12 +4883,9 @@ class Battle {
 				if (this.endCallback) this.endCallback(this);
 				return;
 			}
-			let ret;
 			if (this.paused && !this.fastForward) return;
-			if (!ret) {
-				this.run(this.activityQueue[this.activityStep]);
-				this.activityStep++;
-			}
+			this.run(this.activityQueue[this.activityStep]);
+			this.activityStep++;
 			animations = this.scene.finishAnimations();
 		}