Fix: use arrow function for IIFE

background/usercss-helper.js

@@ -3,7 +3,7 @@
 'use strict';
 
 // eslint-disable-next-line no-var
-var usercssHelper = (function () {
+var usercssHelper = (() => {
   function buildMeta(style) {
     if (style.usercssData) {
       return Promise.resolve(style);

edit/regexp-tester.js

@@ -3,7 +3,7 @@
 'use strict';
 
 // eslint-disable-next-line no-var
-var regExpTester = (function () {
+var regExpTester = (() => {
   const GET_FAVICON_URL = 'https://www.google.com/s2/favicons?domain=';
   const OWN_ICON = chrome.runtime.getManifest().icons['16'];
   const cachedRegexps = new Map();

install-usercss/install-usercss.js

@@ -2,7 +2,7 @@
 
 'use strict';
 
-(function () {
+(() => {
   const params = getParams();
   let liveReload = false;
   let installed = false;

js/localization.js

@@ -103,7 +103,7 @@ function tNodeList(nodes) {
 
 function tDocLoader() {
   t.DOMParser = new DOMParser();
-  t.cache = (function () {
+  t.cache = (() => {
     try {
       return JSON.parse(localStorage.L10N);
     } catch (e) {}

js/moz-parser.js

@@ -3,7 +3,7 @@
 'use strict';
 
 // eslint-disable-next-line no-var
-var mozParser = (function () {
+var mozParser = (() => {
   // direct & reverse mapping of @-moz-document keywords and internal property names
   const propertyToCss = {urls: 'url', urlPrefixes: 'url-prefix', domains: 'domain', regexps: 'regexp'};
   const CssToProperty = {'url': 'urls', 'url-prefix': 'urlPrefixes', 'domain': 'domains', 'regexp': 'regexps'};

js/script-loader.js

@@ -2,7 +2,7 @@
 
 // loadScript(script: Array<Promise|string>|string): Promise
 // eslint-disable-next-line no-var
-var loadScript = (function () {
+var loadScript = (() => {
   const cache = new Map();
 
   function inject(file) {

js/usercss.js

@@ -3,7 +3,7 @@
 'use strict';
 
 // eslint-disable-next-line no-var
-var usercss = (function () {
+var usercss = (() => {
   // true for global, false for private
   const METAS = {
     __proto__: null,
@@ -99,7 +99,7 @@ var usercss = (function () {
     }
   };
 
-  const colorParser = (function () {
+  const colorParser = (() => {
     const el = document.createElement('div');
     // https://bugs.webkit.org/show_bug.cgi?id=14563
     document.head.appendChild(el);