diff --git a/.eslintrc.json b/.eslintrc.json
index 5f5867080..904444837 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -62,7 +62,6 @@
 		"no-use-before-define": "warn",
 		"no-useless-concat": "warn",
 		"no-var": "warn",
-		"prefer-const": "warn",
 		"unicorn/prefer-string-slice": "warn"
 	}
 }
diff --git a/modules/twinklebatchprotect.js b/modules/twinklebatchprotect.js
index 6f745f26d..8e7c61486 100644
--- a/modules/twinklebatchprotect.js
+++ b/modules/twinklebatchprotect.js
@@ -180,7 +180,8 @@ Twinkle.batchprotect.callback = function twinklebatchprotectCallback() {
 		pages.sort(Twinkle.sortByNamespace);
 		pages.forEach((page) => {
 			const metadata = [];
-			let missing = !!page.missing, editProt;
+			const missing = !!page.missing;
+			let editProt;
 
 			if (missing) {
 				metadata.push('page does not exist');
diff --git a/modules/twinkleblock.js b/modules/twinkleblock.js
index 16c39050c..3b085e756 100644
--- a/modules/twinkleblock.js
+++ b/modules/twinkleblock.js
@@ -2,7 +2,8 @@
 
 (function() {
 
-let api = new mw.Api(), relevantUserName, blockedUserName;
+const api = new mw.Api();
+let relevantUserName, blockedUserName;
 const menuFormattedNamespaces = $.extend({}, mw.config.get('wgFormattedNamespaces'));
 menuFormattedNamespaces[0] = '(Article)';
 
@@ -156,8 +157,8 @@ Twinkle.block.fetchedData = {};
 // Processes the data from a a query response, separated from
 // Twinkle.block.fetchUserInfo to allow reprocessing of already-fetched data
 Twinkle.block.processUserInfo = function twinkleblockProcessUserInfo(data, fn) {
-	let blockinfo = data.query.blocks[0],
-		userinfo = data.query.users[0];
+	let blockinfo = data.query.blocks[0];
+	const userinfo = data.query.users[0];
 	// If an IP is blocked *and* rangeblocked, the above finds
 	// whichever block is more recent, not necessarily correct.
 	// Three seems... unlikely
@@ -296,7 +297,8 @@ Twinkle.block.callback.change_block64 = function twinkleblockCallbackChangeBlock
 };
 
 Twinkle.block.callback.change_action = function twinkleblockCallbackChangeAction(e) {
-	let field_preset, field_template_options, field_block_options, $form = $(e.target.form);
+	let field_preset, field_template_options, field_block_options;
+	const $form = $(e.target.form);
 	// Make ifs shorter
 	const blockBox = $form.find('[name=actiontype][value=block]').is(':checked');
 	const templateBox = $form.find('[name=actiontype][value=template]').is(':checked');
@@ -1572,7 +1574,8 @@ Twinkle.block.callback.toggle_ds_reason = function twinkleblockCallbackToggleDSR
 };
 
 Twinkle.block.callback.update_form = function twinkleblockCallbackUpdateForm(e, data) {
-	let form = e.target.form, expiry = data.expiry;
+	const form = e.target.form;
+	let expiry = data.expiry;
 
 	// don't override original expiry if useInitialOptions is set
 	if (!data.useInitialOptions) {
@@ -1723,11 +1726,11 @@ Twinkle.block.callback.preview = function twinkleblockcallbackPreview(form) {
 };
 
 Twinkle.block.callback.evaluate = function twinkleblockCallbackEvaluate(e) {
-	let $form = $(e.target),
+	const $form = $(e.target),
 		toBlock = $form.find('[name=actiontype][value=block]').is(':checked'),
 		toWarn = $form.find('[name=actiontype][value=template]').is(':checked'),
-		toPartial = $form.find('[name=actiontype][value=partial]').is(':checked'),
-		blockoptions = {}, templateoptions = {};
+		toPartial = $form.find('[name=actiontype][value=partial]').is(':checked');
+	let blockoptions = {}, templateoptions = {};
 
 	Twinkle.block.callback.saveFieldset($form.find('[name=field_block_options]'));
 	Twinkle.block.callback.saveFieldset($form.find('[name=field_template_options]'));
@@ -1916,7 +1919,8 @@ Twinkle.block.callback.issue_template = function twinkleblockCallbackIssueTempla
 };
 
 Twinkle.block.callback.getBlockNoticeWikitext = function(params) {
-	let text = '{{', settings = Twinkle.block.blockPresetsInfo[params.template];
+	let text = '{{';
+	const settings = Twinkle.block.blockPresetsInfo[params.template];
 	if (!settings.nonstandard) {
 		text += 'subst:' + params.template;
 		if (params.article && settings.pageParam) {
@@ -1990,10 +1994,10 @@ Twinkle.block.callback.getBlockNoticeWikitext = function(params) {
 };
 
 Twinkle.block.callback.main = function twinkleblockcallbackMain(pageobj) {
-	let params = pageobj.getCallbackParameters(),
+	const params = pageobj.getCallbackParameters(),
 		date = new Morebits.Date(pageobj.getLoadTime()),
-		messageData = params.messageData,
-		text;
+		messageData = params.messageData;
+	let text;
 
 	params.indefinite = Morebits.string.isInfinity(params.expiry);
 
@@ -2003,7 +2007,8 @@ Twinkle.block.callback.main = function twinkleblockcallbackMain(pageobj) {
 	} else {
 		text = pageobj.getPageText();
 
-		let dateHeaderRegex = date.monthHeaderRegex(), dateHeaderRegexLast, dateHeaderRegexResult;
+		const dateHeaderRegex = date.monthHeaderRegex();
+		let dateHeaderRegexLast, dateHeaderRegexResult;
 		while ((dateHeaderRegexLast = dateHeaderRegex.exec(text)) !== null) {
 			dateHeaderRegexResult = dateHeaderRegexLast;
 		}
diff --git a/modules/twinkleconfig.js b/modules/twinkleconfig.js
index 6e11c3fb4..124b64832 100644
--- a/modules/twinkleconfig.js
+++ b/modules/twinkleconfig.js
@@ -1075,7 +1075,8 @@ Twinkle.config.init = function twinkleconfigInit() {
 				}
 				cell = document.createElement('td');
 
-				let label, input, gotPref = Twinkle.getPref(pref.name);
+				let label, input;
+				const gotPref = Twinkle.getPref(pref.name);
 				switch (pref.type) {
 
 					case 'boolean': // create a checkbox
@@ -1295,9 +1296,11 @@ Twinkle.config.init = function twinkleconfigInit() {
 		// Styled in twinkle.css
 		box.setAttribute('id', 'twinkle-config-headerbox');
 
-		let link,
-			scriptPageName = mw.config.get('wgPageName').slice(mw.config.get('wgPageName').lastIndexOf('/') + 1,
-				mw.config.get('wgPageName').lastIndexOf('.js'));
+		let link;
+		const scriptPageName = mw.config.get('wgPageName').slice(
+			mw.config.get('wgPageName').lastIndexOf('/') + 1,
+			mw.config.get('wgPageName').lastIndexOf('.js')
+		);
 
 		if (scriptPageName === 'twinkleoptions') {
 			// place "why not try the preference panel" notice
diff --git a/modules/twinkleprotect.js b/modules/twinkleprotect.js
index e34bb0a8c..3bc6ada64 100644
--- a/modules/twinkleprotect.js
+++ b/modules/twinkleprotect.js
@@ -173,7 +173,8 @@ Twinkle.protect.fetchProtectionLevel = function twinkleprotectFetchProtectionLev
 
 		const pageid = protectData[0].query.pageids[0];
 		const page = protectData[0].query.pages[pageid];
-		let current = {}, adminEditDeferred;
+		const current = {};
+		let adminEditDeferred;
 
 		// Save requested page's watched status for later in case needed when filing request
 		Twinkle.protect.watched = page.watchlistexpiry || page.watched === '';
diff --git a/modules/twinklespeedy.js b/modules/twinklespeedy.js
index 1d2a681b1..0c39c65c4 100644
--- a/modules/twinklespeedy.js
+++ b/modules/twinklespeedy.js
@@ -39,9 +39,8 @@ Twinkle.speedy.hasCSD = !!$('#delete-reason').length;
 
 // Prepares the speedy deletion dialog and displays it
 Twinkle.speedy.initDialog = function twinklespeedyInitDialog(callbackfunc) {
-	let dialog;
 	Twinkle.speedy.dialog = new Morebits.SimpleWindow(Twinkle.getPref('speedyWindowWidth'), Twinkle.getPref('speedyWindowHeight'));
-	dialog = Twinkle.speedy.dialog;
+	const dialog = Twinkle.speedy.dialog;
 	dialog.setTitle('Choose criteria for speedy deletion');
 	dialog.setScriptName('Twinkle');
 	dialog.addFooterLink('Speedy deletion policy', 'WP:CSD');
@@ -1140,8 +1139,8 @@ Twinkle.speedy.callbacks = {
 		}
 
 		if (initialContrib) {
-			let usertalkpage = new Morebits.wiki.Page('User talk:' + initialContrib, 'Notifying initial contributor (' + initialContrib + ')'),
-				notifytext, i, editsummary;
+			const usertalkpage = new Morebits.wiki.Page('User talk:' + initialContrib, 'Notifying initial contributor (' + initialContrib + ')');
+			let notifytext, i, editsummary;
 
 			// special cases: "db" and "db-multiple"
 			if (params.normalizeds.length > 1) {
@@ -1367,8 +1366,8 @@ Twinkle.speedy.callbacks = {
 
 			// given the params, builds the template and also adds the user talk page parameters to the params that were passed in
 			// returns => [<string> wikitext, <object> utparams]
-			let buildData = Twinkle.speedy.callbacks.getTemplateCodeAndParams(params),
-				code = buildData[0];
+			const buildData = Twinkle.speedy.callbacks.getTemplateCodeAndParams(params);
+			let code = buildData[0];
 			params.utparams = buildData[1];
 
 			// Set the correct value for |ts= parameter in {{db-g13}}
diff --git a/modules/twinkletag.js b/modules/twinkletag.js
index 6421d016f..fb1f5d1b4 100644
--- a/modules/twinkletag.js
+++ b/modules/twinkletag.js
@@ -351,7 +351,6 @@ Twinkle.tag.callback = function twinkletagCallback() {
 		const evt = document.createEvent('Event');
 		evt.initEvent('change', true, true);
 		result.sortorder.dispatchEvent(evt);
-
 	} else {
 		// Redirects and files: Add a link to each template's description page
 		Morebits.QuickForm.getElements(result, 'tags').forEach(generateLinks);
@@ -1589,7 +1588,8 @@ Twinkle.tag.callbacks = {
 			return;
 		}
 
-		let tagRe, tagText = '', tags = [], groupableTags = [], groupableExistingTags = [];
+		let tagRe, tagText = '', tags = [];
+		const groupableTags = [], groupableExistingTags = [];
 		// Executes first: addition of selected tags
 
 		/**
@@ -1806,10 +1806,12 @@ Twinkle.tag.callbacks = {
 	},
 
 	redirect: function redirect(pageobj) {
-		let params = pageobj.getCallbackParameters(),
-			pageText = pageobj.getPageText(),
-			tagRe, tagText = '', summaryText = 'Added',
-			tags = [], i;
+		const params = pageobj.getCallbackParameters(),
+			tags = [];
+		let pageText = pageobj.getPageText(),
+			tagRe, tagText = '',
+			summaryText = 'Added',
+			i;
 
 		for (i = 0; i < params.tags.length; i++) {
 			tagRe = new RegExp('(\\{\\{' + params.tags[i] + '(\\||\\}\\}))', 'im');
diff --git a/modules/twinklewarn.js b/modules/twinklewarn.js
index cf0724fbd..51ad7d398 100644
--- a/modules/twinklewarn.js
+++ b/modules/twinklewarn.js
@@ -54,9 +54,8 @@ Twinkle.warn.callback = function twinklewarnCallback() {
 		return;
 	}
 
-	let dialog;
 	Twinkle.warn.dialog = new Morebits.SimpleWindow(600, 440);
-	dialog = Twinkle.warn.dialog;
+	const dialog = Twinkle.warn.dialog;
 	dialog.setTitle('Warn/notify user');
 	dialog.setScriptName('Twinkle');
 	dialog.addFooterLink('Choosing a warning level', 'WP:UWUL#Levels');
@@ -1706,9 +1705,7 @@ Twinkle.warn.callbacks = {
 		// Provided on autolevel, not otherwise
 		templatename = templatename || input.sub_group;
 		const linkedarticle = input.article;
-		let templatetext;
-
-		templatetext = Twinkle.warn.callbacks.getWarningWikitext(templatename, linkedarticle,
+		const templatetext = Twinkle.warn.callbacks.getWarningWikitext(templatename, linkedarticle,
 			input.reason, input.main_group === 'custom');
 
 		form.previewer.beginRender(templatetext, 'User_talk:' + mw.config.get('wgRelevantUserName')); // Force wikitext/correct username
diff --git a/modules/twinklexfd.js b/modules/twinklexfd.js
index 59034ac58..964a97c9a 100644
--- a/modules/twinklexfd.js
+++ b/modules/twinklexfd.js
@@ -424,8 +424,8 @@ Twinkle.xfd.callback.change_category = function twinklexfdCallbackChangeCategory
 				label: 'Choose type of action wanted:',
 				name: 'xfdcat',
 				event: function(e) {
-					let target = e.target,
-						tfdtarget = target.form.tfdtarget;
+					const target = e.target;
+					let tfdtarget = target.form.tfdtarget;
 					// add/remove extra input box
 					if (target.value === 'tfm' && !tfdtarget) {
 						tfdtarget = new Morebits.QuickForm.Element({
@@ -554,9 +554,9 @@ Twinkle.xfd.callback.change_category = function twinklexfdCallbackChangeCategory
 				label: 'Choose type of action wanted:',
 				name: 'xfdcat',
 				event: function(e) {
-					let value = e.target.value,
-						cfdtarget = e.target.form.cfdtarget,
-						cfdtarget2 = e.target.form.cfdtarget2;
+					const value = e.target.value,
+						cfdtarget = e.target.form.cfdtarget;
+					let cfdtarget2 = e.target.form.cfdtarget2;
 
 					// update enabled status
 					cfdtarget.disabled = value === 'cfd' || value === 'sfd-t';
diff --git a/morebits.js b/morebits.js
index c015ac77a..11bfe914e 100644
--- a/morebits.js
+++ b/morebits.js
@@ -266,7 +266,8 @@ Morebits.namespaceRegex = function(namespaces) {
 	if (!Array.isArray(namespaces)) {
 		namespaces = [namespaces];
 	}
-	let aliases = [], regex;
+	const aliases = [];
+	let regex;
 	$.each(mw.config.get('wgNamespaceIds'), (name, number) => {
 		if (namespaces.indexOf(number) !== -1) {
 			// Namespaces are completely agnostic as to case,
@@ -3831,7 +3832,8 @@ Morebits.wiki.page = function(pageName, status) {
 			return; // abort
 		}
 
-		let page = response.pages[0], rev;
+		const page = response.pages[0];
+		let rev;
 		ctx.pageExists = !page.missing;
 		if (ctx.pageExists) {
 			rev = page.revisions[0];