rework eslint config (#11615)

* rework eslint config

- use explicit config that only enables rules
- upgrade eslint to 7.1.0
- add new plugins with selected rules enabled
- fix discovered issues, remove global wipPrefixes

* remove if

* undo template change

* add disabled rules as well for easier config updating

* add missing disabled rule

* update eslint and plugins

* fix new violation

* remove deprecated rules

Co-authored-by: Lauris BH <lauris@nix.lv>

web_src/js/index.js

@@ -1,4 +1,3 @@
-/* globals wipPrefixes */
 /* exported timeAddManual, toggleStopwatch, cancelStopwatch */
 /* exported toggleDeadlineForm, setDeadline, updateDeadline, deleteDependencyModal, cancelCodeComment, onOAuthLoginClick */
 
@@ -2178,8 +2177,9 @@ function initWipTitle() {
     $issueTitle.focus();
     const value = $issueTitle.val().trim().toUpperCase();
 
-    for (const i in wipPrefixes) {
-      if (value.startsWith(wipPrefixes[i].toUpperCase())) {
+    const wipPrefixes = $('.title_wip_desc').data('wip-prefixes');
+    for (const prefix of wipPrefixes) {
+      if (value.startsWith(prefix.toUpperCase())) {
         return;
       }
     }
@@ -2472,10 +2472,9 @@ $(document).ready(async () => {
     'div.repository.settings.collaboration': initRepositoryCollaboration
   };
 
-  let selector;
-  for (selector in routes) {
+  for (const [selector, fn] of Object.entries(routes)) {
     if ($(selector).length > 0) {
-      routes[selector]();
+      fn();
       break;
     }
   }
@@ -2972,13 +2971,13 @@ function initVueComponents() {
       repoClass(repo) {
         if (repo.fork) {
           return 'octicon-repo-forked';
-        } if (repo.mirror) {
+        } else if (repo.mirror) {
           return 'octicon-repo-clone';
-        } if (repo.template) {
+        } else if (repo.template) {
           return `octicon-repo-template${repo.private ? '-private' : ''}`;
-        } if (repo.private) {
+        } else if (repo.private) {
           return 'octicon-lock';
-        } if (repo.internal) {
+        } else if (repo.internal) {
           return 'octicon-internal-repo';
         }
         return 'octicon-repo';