refactor SingleFileDiff class to ES module syntax

app/assets/javascripts/diff.js

@@ -2,6 +2,7 @@
 import './lib/utils/url_utility';
 import FilesCommentButton from './files_comment_button';
+import SingleFileDiff from './single_file_diff';
 const UNFOLD_COUNT = 20;
 let isBound = false;
@@ -10,7 +11,11 @@ class Diff {
   constructor() {
     const $diffFile = $('.files .diff-file');
-    $diffFile.singleFileDiff();
+    $diffFile.each((index, file) => {
+      if (!$.data(file, 'singleFileDiff')) {
+        $.data(file, 'singleFileDiff', new SingleFileDiff(file));
+      }
+    });
     FilesCommentButton.init($diffFile);

app/assets/javascripts/main.js

@@ -144,7 +144,6 @@ import './right_sidebar';
 import './search';
 import './search_autocomplete';
 import './signin_tabs_memoizer';
-import './single_file_diff';
 import './smart_interval';
 import './snippets_list';
 import './star';

app/assets/javascripts/single_file_diff.js

@@ -7,7 +7,7 @@ const LOADING_HTML = '<i class="fa fa-spinner fa-spin"></i>';
 const ERROR_HTML = '<div class="nothing-here-block"><i class="fa fa-warning"></i> Could not load diff</div>';
 const COLLAPSED_HTML = '<div class="nothing-here-block diff-collapsed">This diff is collapsed. <a class="click-to-expand">Click to expand it.</a></div>';
-class SingleFileDiff {
+export default class SingleFileDiff {
   constructor(file) {
     this.file = file;
     this.toggleDiff = this.toggleDiff.bind(this);
@@ -81,13 +81,3 @@ class SingleFileDiff {
     })(this));
   }
 }
-
-$.fn.singleFileDiff = function() {
-  return this.each(function() {
-    if (!$.data(this, 'singleFileDiff')) {
-      return $.data(this, 'singleFileDiff', new window.SingleFileDiff(this));
-    }
-  });
-};
-
-window.SingleFileDiff = SingleFileDiff;

spec/javascripts/merge_request_tabs_spec.js

@@ -6,7 +6,6 @@ import '~/commit/pipelines/pipelines_bundle';
 import '~/breakpoints';
 import '~/lib/utils/common_utils';
 import '~/diff';
-import '~/single_file_diff';
 import '~/files_comment_button';
 import '~/notes';
 import 'vendor/jquery.scrollTo';