Split index.js to separate files (#17315)

* split `index.js` to separate files

* tune clipboard

* fix promise

* fix document

* remove intermediate empty file

* fix async event listener

* use `export function` instead of `export {}`, add more comments

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>

web_src/js/features/comp/CommentSimpleMDE.js

@@ -0,0 +1,72 @@
+import attachTribute from '../tribute.js';
+
+export function createCommentSimpleMDE($editArea) {
+  if ($editArea.length === 0) {
+    return null;
+  }
+
+  const simplemde = new SimpleMDE({
+    autoDownloadFontAwesome: false,
+    element: $editArea[0],
+    forceSync: true,
+    renderingConfig: {
+      singleLineBreaks: false
+    },
+    indentWithTabs: false,
+    tabSize: 4,
+    spellChecker: false,
+    toolbar: ['bold', 'italic', 'strikethrough', '|',
+      'heading-1', 'heading-2', 'heading-3', 'heading-bigger', 'heading-smaller', '|',
+      'code', 'quote', '|', {
+        name: 'checkbox-empty',
+        action(e) {
+          const cm = e.codemirror;
+          cm.replaceSelection(`\n- [ ] ${cm.getSelection()}`);
+          cm.focus();
+        },
+        className: 'fa fa-square-o',
+        title: 'Add Checkbox (empty)',
+      },
+      {
+        name: 'checkbox-checked',
+        action(e) {
+          const cm = e.codemirror;
+          cm.replaceSelection(`\n- [x] ${cm.getSelection()}`);
+          cm.focus();
+        },
+        className: 'fa fa-check-square-o',
+        title: 'Add Checkbox (checked)',
+      }, '|',
+      'unordered-list', 'ordered-list', '|',
+      'link', 'image', 'table', 'horizontal-rule', '|',
+      'clean-block', '|',
+      {
+        name: 'revert-to-textarea',
+        action(e) {
+          e.toTextArea();
+        },
+        className: 'fa fa-file',
+        title: 'Revert to simple textarea',
+      },
+    ]
+  });
+  $(simplemde.codemirror.getInputField()).addClass('js-quick-submit');
+  simplemde.codemirror.setOption('extraKeys', {
+    Enter: () => {
+      const tributeContainer = document.querySelector('.tribute-container');
+      if (!tributeContainer || tributeContainer.style.display === 'none') {
+        return CodeMirror.Pass;
+      }
+    },
+    Backspace: (cm) => {
+      if (cm.getInputField().trigger) {
+        cm.getInputField().trigger('input');
+      }
+      cm.execCommand('delCharBefore');
+    }
+  });
+  attachTribute(simplemde.codemirror.getInputField(), {mentions: true, emoji: true});
+  $editArea.data('simplemde', simplemde);
+  $(simplemde.codemirror.getInputField()).data('simplemde', simplemde);
+  return simplemde;
+}