diff --git a/modules/.eslintrc.json b/modules/.eslintrc.json
index 07eed576..d022e3f0 100644
--- a/modules/.eslintrc.json
+++ b/modules/.eslintrc.json
@@ -10,7 +10,6 @@
 	},
 	"rules": {
 		"max-len": "off",
-		"no-jquery/no-global-selector": "off",
-		"prefer-const": "warn"
+		"no-jquery/no-global-selector": "off"
 	}
 }
diff --git a/modules/jquery.wikiEditor.dialogs.config.js b/modules/jquery.wikiEditor.dialogs.config.js
index 57145bca..8531cebd 100644
--- a/modules/jquery.wikiEditor.dialogs.config.js
+++ b/modules/jquery.wikiEditor.dialogs.config.js
@@ -476,7 +476,7 @@ module.exports = {
 						}
 					},
 					open: function () {
-						let magicWordsI18N = configData.magicWords,
+						const magicWordsI18N = configData.magicWords,
 							fileData = {
 								pre: '',
 								post: '',
@@ -550,7 +550,7 @@ module.exports = {
 
 						// Pre-fill the text fields based on the current selection
 						if ( selection !== '' ) {
-							fileData = Object.assign( fileData, parseFileSyntax( selection ) );
+							Object.assign( fileData, parseFileSyntax( selection ) );
 						}
 
 						// Initialize the form fields
@@ -831,7 +831,6 @@ module.exports = {
 							$( this ).data( 'offset', 0 );
 						} else {
 
-							let start, end;
 							if ( mode === 'replace' ) {
 
 								let actualReplacement;
@@ -871,8 +870,8 @@ module.exports = {
 									match = { index: 0, 0: { length: 0 } };
 								}
 							}
-							start = offset + match.index;
-							end = start + match[ 0 ].length;
+							const start = offset + match.index;
+							const end = start + match[ 0 ].length;
 
 							$( this ).data( 'matchIndex', start );
 
diff --git a/modules/jquery.wikiEditor.toolbar.config.js b/modules/jquery.wikiEditor.toolbar.config.js
index 6b42b53f..e8f8149f 100644
--- a/modules/jquery.wikiEditor.toolbar.config.js
+++ b/modules/jquery.wikiEditor.toolbar.config.js
@@ -3,10 +3,9 @@
  *
  * @private
  */
-let configData = require( './data.json' ),
+const configData = require( './data.json' ),
 	fileNamespace = mw.config.get( 'wgFormattedNamespaces' )[ 6 ],
-	specialCharacterGroups = require( 'mediawiki.language.specialCharacters' ),
-	toolbarConfig;
+	specialCharacterGroups = require( 'mediawiki.language.specialCharacters' );
 
 /**
  * Replace link targets from example messages with hash
@@ -26,7 +25,7 @@ function delink( $message ) {
 	return $div.html();
 }
 
-toolbarConfig = {
+const toolbarConfig = {
 	toolbar: {
 		// Main section
 		main: {
diff --git a/modules/jquery.wikiEditor.toolbar.js b/modules/jquery.wikiEditor.toolbar.js
index a27a5c03..8dd46756 100644
--- a/modules/jquery.wikiEditor.toolbar.js
+++ b/modules/jquery.wikiEditor.toolbar.js
@@ -13,7 +13,6 @@ const toolbarModule = {
 		addToToolbar: function ( context, data ) {
 
 			for ( const type in data ) {
-				let i;
 				switch ( type ) {
 					case 'sections': {
 						const $sections = context.modules.toolbar.$toolbar.find( 'div.sections' );
@@ -98,7 +97,7 @@ const toolbarModule = {
 							'div[rel="' + data.section + '"].section ' +
 							'div[rel="' + data.page + '"].page table'
 						);
-						for ( i = 0; i < data.rows.length; i++ ) {
+						for ( let i = 0; i < data.rows.length; i++ ) {
 							// Row
 							$table.append( toolbarModule.fn.buildRow( context, data.rows[ i ] ) );
 						}
@@ -113,7 +112,7 @@ const toolbarModule = {
 							'div[rel="' + data.page + '"].page div'
 						);
 						const actions = $characters.data( 'actions' );
-						for ( i = 0; i < data.characters.length; i++ ) {
+						for ( let i = 0; i < data.characters.length; i++ ) {
 							// Character
 							$characters.append(
 								$( toolbarModule.fn.buildCharacter( data.characters[ i ], actions ) )
@@ -502,7 +501,6 @@ const toolbarModule = {
 			return $page;
 		},
 		reallyBuildPage: function ( context, id, page, $page ) {
-			let i;
 			switch ( page.layout ) {
 				case 'table': {
 					$page.addClass( 'page-table' );
@@ -511,7 +509,7 @@ const toolbarModule = {
 						html += toolbarModule.fn.buildHeading( context, page.headings );
 					}
 					if ( 'rows' in page ) {
-						for ( i = 0; i < page.rows.length; i++ ) {
+						for ( let i = 0; i < page.rows.length; i++ ) {
 							html += toolbarModule.fn.buildRow( context, page.rows[ i ] );
 						}
 					}
@@ -535,7 +533,7 @@ const toolbarModule = {
 					}
 					if ( 'characters' in page ) {
 						let html = '';
-						for ( i = 0; i < page.characters.length; i++ ) {
+						for ( let i = 0; i < page.characters.length; i++ ) {
 							html += toolbarModule.fn.buildCharacter( page.characters[ i ], actions );
 						}
 						$characters
@@ -769,8 +767,8 @@ const toolbarModule = {
 			}
 		},
 		updateBookletSelection: function ( context, id, $pages, $index ) {
-			let cookie = 'wikiEditor-' + context.instance + '-booklet-' + id + '-page',
-				selected = $.cookie( cookie );
+			const cookie = 'wikiEditor-' + context.instance + '-booklet-' + id + '-page';
+			let selected = $.cookie( cookie );
 			// Re-save cookie
 			if ( selected !== null ) {
 				$.cookie( cookie, selected, { expires: 30, path: '/' } );