eslint - remove operator-assignment & format

.eslintrc.js

@@ -19,7 +19,6 @@ const legacyCode = {
   'no-prototype-builtins': 'off',
   'no-restricted-syntax': 'off',
   'no-this-before-super': 'off',
-  'operator-assignment': 'off',
   'prefer-destructuring': 'off',
   'prefer-object-spread': 'off',
   'prefer-promise-reject-errors': 'off',

client/src/components/Draftail/CommentableEditor/CommentableEditor.tsx

@@ -482,7 +482,7 @@ export function findLeastCommonCommentId(block: ContentBlock, offset: number) {
       findCommentStyleRanges(
         block,
         () => {
-          counter = counter + 1;
+          counter += 1;
         },
         (metadata) =>
           metadata.getStyle().some((rangeStyle) => rangeStyle === style),

wagtail/snippets/static_src/wagtailsnippets/js/snippet-multiple-select.js

@@ -21,7 +21,7 @@ var updateDeleteButton = function (anySelected, newState) {
     // hide button and add url
     $deleteButton.removeClass('u-hidden');
     var url = $deleteButton.data('url');
-    url = url + $.param({ id: ids }, true);
+    url += $.param({ id: ids }, true);
     $deleteButton.attr('href', url);
   } else {
     // show button and remove url