diff --git a/app/assets/javascripts/behaviors/markdown/copy_as_gfm.js b/app/assets/javascripts/behaviors/markdown/copy_as_gfm.js
index fe02096d903..947d019c725 100644
--- a/app/assets/javascripts/behaviors/markdown/copy_as_gfm.js
+++ b/app/assets/javascripts/behaviors/markdown/copy_as_gfm.js
@@ -1,320 +1,8 @@
-/* eslint-disable object-shorthand, no-unused-vars, no-use-before-define, no-restricted-syntax, guard-for-in, no-continue */
-
 import $ from 'jquery';
-import _ from 'underscore';
-import { insertText, getSelectedFragment, nodeMatchesSelector } from '~/lib/utils/common_utils';
-import { placeholderImage } from '~/lazy_loader';
-
-const gfmRules = {
-  // The filters referenced in lib/banzai/pipeline/gfm_pipeline.rb convert
-  // GitLab Flavored Markdown (GFM) to HTML.
-  // These handlers consequently convert that same HTML to GFM to be copied to the clipboard.
-  // Every filter in lib/banzai/pipeline/gfm_pipeline.rb that generates HTML
-  // from GFM should have a handler here, in reverse order.
-  // The GFM-to-HTML-to-GFM cycle is tested in spec/features/copy_as_gfm_spec.rb.
-  InlineDiffFilter: {
-    'span.idiff.addition'(el, text) {
-      return `{+${text}+}`;
-    },
-    'span.idiff.deletion'(el, text) {
-      return `{-${text}-}`;
-    },
-  },
-  TaskListFilter: {
-    'input[type=checkbox].task-list-item-checkbox'(el) {
-      return `[${el.checked ? 'x' : ' '}]`;
-    },
-  },
-  ReferenceFilter: {
-    '.tooltip'(el) {
-      return '';
-    },
-    'a.gfm:not([data-link=true])'(el, text) {
-      return el.dataset.original || text;
-    },
-  },
-  AutolinkFilter: {
-    a(el, text) {
-      // Fallback on the regular MarkdownFilter's `a` handler.
-      if (text !== el.getAttribute('href')) return false;
-
-      return text;
-    },
-  },
-  TableOfContentsFilter: {
-    'ul.section-nav'(el) {
-      return '[[_TOC_]]';
-    },
-  },
-  EmojiFilter: {
-    'img.emoji'(el) {
-      return el.getAttribute('alt');
-    },
-    'gl-emoji'(el) {
-      return `:${el.getAttribute('data-name')}:`;
-    },
-  },
-  ImageLinkFilter: {
-    'a.no-attachment-icon'(el, text) {
-      return text;
-    },
-  },
-  ImageLazyLoadFilter: {
-    img(el, text) {
-      return `![${el.getAttribute('alt')}](${el.getAttribute('src')})`;
-    },
-  },
-  VideoLinkFilter: {
-    '.video-container'(el) {
-      const videoEl = el.querySelector('video');
-      if (!videoEl) return false;
-
-      return CopyAsGFM.nodeToGFM(videoEl);
-    },
-    video(el) {
-      return `![${el.dataset.title}](${el.getAttribute('src')})`;
-    },
-  },
-  MermaidFilter: {
-    'svg.mermaid'(el, text) {
-      const sourceEl = el.querySelector('text.source');
-      if (!sourceEl) return false;
-
-      return `\`\`\`mermaid\n${CopyAsGFM.nodeToGFM(sourceEl)}\n\`\`\``;
-    },
-    'svg.mermaid style, svg.mermaid g'(el, text) {
-      // We don't want to include the content of these elements in the copied text.
-      return '';
-    },
-  },
-  MathFilter: {
-    'pre.code.math[data-math-style=display]'(el, text) {
-      return `\`\`\`math\n${text.trim()}\n\`\`\``;
-    },
-    'code.code.math[data-math-style=inline]'(el, text) {
-      return `$\`${text}\`$`;
-    },
-    'span.katex-display span.katex-mathml'(el) {
-      const mathAnnotation = el.querySelector('annotation[encoding="application/x-tex"]');
-      if (!mathAnnotation) return false;
-
-      return `\`\`\`math\n${CopyAsGFM.nodeToGFM(mathAnnotation)}\n\`\`\``;
-    },
-    'span.katex-mathml'(el) {
-      const mathAnnotation = el.querySelector('annotation[encoding="application/x-tex"]');
-      if (!mathAnnotation) return false;
-
-      return `$\`${CopyAsGFM.nodeToGFM(mathAnnotation)}\`$`;
-    },
-    'span.katex-html'(el) {
-      // We don't want to include the content of this element in the copied text.
-      return '';
-    },
-    'annotation[encoding="application/x-tex"]'(el, text) {
-      return text.trim();
-    },
-  },
-  SanitizationFilter: {
-    'a[name]:not([href]):empty'(el) {
-      return el.outerHTML;
-    },
-    dl(el, text) {
-      let lines = text
-        .replace(/\n\n/g, '\n')
-        .trim()
-        .split('\n');
-      // Add two spaces to the front of subsequent list items lines,
-      // or leave the line entirely blank.
-      lines = lines.map(l => {
-        const line = l.trim();
-        if (line.length === 0) return '';
-
-        return `  ${line}`;
-      });
-
-      return `<dl>\n${lines.join('\n')}\n</dl>\n`;
-    },
-    'dt, dd, summary, details'(el, text) {
-      const tag = el.nodeName.toLowerCase();
-      return `<${tag}>${text}</${tag}>\n`;
-    },
-    'sup, sub, kbd, q, samp, var, ruby, rt, rp, abbr'(el, text) {
-      const tag = el.nodeName.toLowerCase();
-      return `<${tag}>${text}</${tag}>`;
-    },
-  },
-  SyntaxHighlightFilter: {
-    'pre.code.highlight'(el, t) {
-      const text = t.trimRight();
-
-      let lang = el.getAttribute('lang');
-      if (!lang || lang === 'plaintext') {
-        lang = '';
-      }
-
-      // Prefixes lines with 4 spaces if the code contains triple backticks
-      if (lang === '' && text.match(/^```/gm)) {
-        return text
-          .split('\n')
-          .map(l => {
-            const line = l.trim();
-            if (line.length === 0) return '';
-
-            return `    ${line}`;
-          })
-          .join('\n');
-      }
-
-      return `\`\`\`${lang}\n${text}\n\`\`\``;
-    },
-    'pre > code'(el, text) {
-      // Don't wrap code blocks in ``
-      return text;
-    },
-  },
-  MarkdownFilter: {
-    br(el) {
-      // Two spaces at the end of a line are turned into a BR
-      return '  ';
-    },
-    code(el, text) {
-      let backtickCount = 1;
-      const backtickMatch = text.match(/`+/);
-      if (backtickMatch) {
-        backtickCount = backtickMatch[0].length + 1;
-      }
-
-      const backticks = Array(backtickCount + 1).join('`');
-      const spaceOrNoSpace = backtickCount > 1 ? ' ' : '';
-
-      return backticks + spaceOrNoSpace + text.trim() + spaceOrNoSpace + backticks;
-    },
-    blockquote(el, text) {
-      return text
-        .trim()
-        .split('\n')
-        .map(s => `> ${s}`.trim())
-        .join('\n');
-    },
-    img(el) {
-      const imageSrc = el.src;
-      const imageUrl = imageSrc && imageSrc !== placeholderImage ? imageSrc : el.dataset.src || '';
-      return `![${el.getAttribute('alt')}](${imageUrl})`;
-    },
-    'a.anchor'(el, text) {
-      // Don't render a Markdown link for the anchor link inside a heading
-      return text;
-    },
-    a(el, text) {
-      return `[${text}](${el.getAttribute('href')})`;
-    },
-    li(el, text) {
-      const lines = text.trim().split('\n');
-      const firstLine = `- ${lines.shift()}`;
-      // Add four spaces to the front of subsequent list items lines,
-      // or leave the line entirely blank.
-      const nextLines = lines.map(s => {
-        if (s.trim().length === 0) return '';
-
-        return `    ${s}`;
-      });
-
-      return `${firstLine}\n${nextLines.join('\n')}`;
-    },
-    ul(el, text) {
-      return text;
-    },
-    ol(el, text) {
-      // LIs get a `- ` prefix by default, which we replace by `1. ` for ordered lists.
-      return text.replace(/^- /gm, '1. ');
-    },
-    h1(el, text) {
-      return `# ${text.trim()}\n`;
-    },
-    h2(el, text) {
-      return `## ${text.trim()}\n`;
-    },
-    h3(el, text) {
-      return `### ${text.trim()}\n`;
-    },
-    h4(el, text) {
-      return `#### ${text.trim()}\n`;
-    },
-    h5(el, text) {
-      return `##### ${text.trim()}\n`;
-    },
-    h6(el, text) {
-      return `###### ${text.trim()}\n`;
-    },
-    strong(el, text) {
-      return `**${text}**`;
-    },
-    em(el, text) {
-      return `_${text}_`;
-    },
-    del(el, text) {
-      return `~~${text}~~`;
-    },
-    hr(el) {
-      // extra leading \n is to ensure that there is a blank line between
-      // a list followed by an hr, otherwise this breaks old redcarpet rendering
-      return '\n-----\n';
-    },
-    p(el, text) {
-      return `${text.trim()}\n`;
-    },
-    table(el) {
-      const theadEl = el.querySelector('thead');
-      const tbodyEl = el.querySelector('tbody');
-      if (!theadEl || !tbodyEl) return false;
-
-      const theadText = CopyAsGFM.nodeToGFM(theadEl);
-      const tbodyText = CopyAsGFM.nodeToGFM(tbodyEl);
-
-      return [theadText, tbodyText].join('\n');
-    },
-    thead(el, text) {
-      const cells = _.map(el.querySelectorAll('th'), cell => {
-        let chars = CopyAsGFM.nodeToGFM(cell).length + 2;
-
-        let before = '';
-        let after = '';
-        const alignment = cell.align || cell.style.textAlign;
-
-        switch (alignment) {
-          case 'center':
-            before = ':';
-            after = ':';
-            chars -= 2;
-            break;
-          case 'right':
-            after = ':';
-            chars -= 1;
-            break;
-          default:
-            break;
-        }
-
-        chars = Math.max(chars, 3);
-
-        const middle = Array(chars + 1).join('-');
-
-        return before + middle + after;
-      });
-
-      const separatorRow = `|${cells.join('|')}|`;
-
-      return [text, separatorRow].join('\n');
-    },
-    tr(el) {
-      const cellEls = el.querySelectorAll('td, th');
-      if (cellEls.length === 0) return false;
-
-      const cells = _.map(cellEls, cell => CopyAsGFM.nodeToGFM(cell));
-      return `| ${cells.join(' | ')} |`;
-    },
-  },
-};
+import { DOMParser } from 'prosemirror-model';
+import { getSelectedFragment } from '~/lib/utils/common_utils';
+import schema from './schema';
+import markdownSerializer from './serializer';
 
 export class CopyAsGFM {
   constructor() {
@@ -347,8 +35,13 @@ export class CopyAsGFM {
     e.preventDefault();
     e.stopPropagation();
 
+    const div = document.createElement('div');
+    div.appendChild(el.cloneNode(true));
+    const html = div.innerHTML;
+
     clipboardData.setData('text/plain', el.textContent);
     clipboardData.setData('text/x-gfm', this.nodeToGFM(el));
+    clipboardData.setData('text/html', html);
   }
 
   static pasteGFM(e) {
@@ -361,7 +54,7 @@ export class CopyAsGFM {
 
     e.preventDefault();
 
-    window.gl.utils.insertText(e.target, (textBefore, textAfter) => {
+    window.gl.utils.insertText(e.target, textBefore => {
       // If the text before the cursor contains an odd number of backticks,
       // we are either inside an inline code span that starts with 1 backtick
       // or a code block that starts with 3 backticks.
@@ -443,75 +136,12 @@ export class CopyAsGFM {
     return codeElement;
   }
 
-  static nodeToGFM(node, respectWhitespaceParam = false) {
-    if (node.nodeType === Node.COMMENT_NODE) {
-      return '';
-    }
+  static nodeToGFM(node) {
+    const wrapEl = document.createElement('div');
+    wrapEl.appendChild(node.cloneNode(true));
+    const doc = DOMParser.fromSchema(schema).parse(wrapEl);
 
-    if (node.nodeType === Node.TEXT_NODE) {
-      return node.textContent;
-    }
-
-    const respectWhitespace =
-      respectWhitespaceParam || (node.nodeName === 'PRE' || node.nodeName === 'CODE');
-
-    const text = this.innerGFM(node, respectWhitespace);
-
-    if (node.nodeType === Node.DOCUMENT_FRAGMENT_NODE) {
-      return text;
-    }
-
-    for (const filter in gfmRules) {
-      const rules = gfmRules[filter];
-
-      for (const selector in rules) {
-        const func = rules[selector];
-
-        if (!nodeMatchesSelector(node, selector)) continue;
-
-        let result;
-        if (func.length === 2) {
-          // if `func` takes 2 arguments, it depends on text.
-          // if there is no text, we don't need to generate GFM for this node.
-          if (text.length === 0) continue;
-
-          result = func(node, text);
-        } else {
-          result = func(node);
-        }
-
-        if (result === false) continue;
-
-        return result;
-      }
-    }
-
-    return text;
-  }
-
-  static innerGFM(parentNode, respectWhitespace = false) {
-    const nodes = parentNode.childNodes;
-
-    const clonedParentNode = parentNode.cloneNode(true);
-    const clonedNodes = Array.prototype.slice.call(clonedParentNode.childNodes, 0);
-
-    for (let i = 0; i < nodes.length; i += 1) {
-      const node = nodes[i];
-      const clonedNode = clonedNodes[i];
-
-      const text = this.nodeToGFM(node, respectWhitespace);
-
-      // `clonedNode.replaceWith(text)` is not yet widely supported
-      clonedNode.parentNode.replaceChild(document.createTextNode(text), clonedNode);
-    }
-
-    let nodeText = clonedParentNode.innerText || clonedParentNode.textContent;
-
-    if (!respectWhitespace) {
-      nodeText = nodeText.trim();
-    }
-
-    return nodeText;
+    return markdownSerializer.serialize(doc);
   }
 }
 
diff --git a/app/assets/javascripts/behaviors/markdown/editor_extensions.js b/app/assets/javascripts/behaviors/markdown/editor_extensions.js
new file mode 100644
index 00000000000..47e5fc65c48
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/editor_extensions.js
@@ -0,0 +1,106 @@
+import Doc from './nodes/doc';
+import Paragraph from './nodes/paragraph';
+import Text from './nodes/text';
+
+import Blockquote from './nodes/blockquote';
+import CodeBlock from './nodes/code_block';
+import HardBreak from './nodes/hard_break';
+import Heading from './nodes/heading';
+import HorizontalRule from './nodes/horizontal_rule';
+import Image from './nodes/image';
+
+import Table from './nodes/table';
+import TableHead from './nodes/table_head';
+import TableBody from './nodes/table_body';
+import TableHeaderRow from './nodes/table_header_row';
+import TableRow from './nodes/table_row';
+import TableCell from './nodes/table_cell';
+
+import Emoji from './nodes/emoji';
+import Reference from './nodes/reference';
+
+import TableOfContents from './nodes/table_of_contents';
+import Video from './nodes/video';
+
+import BulletList from './nodes/bullet_list';
+import OrderedList from './nodes/ordered_list';
+import ListItem from './nodes/list_item';
+
+import DescriptionList from './nodes/description_list';
+import DescriptionTerm from './nodes/description_term';
+import DescriptionDetails from './nodes/description_details';
+
+import TaskList from './nodes/task_list';
+import OrderedTaskList from './nodes/ordered_task_list';
+import TaskListItem from './nodes/task_list_item';
+
+import Summary from './nodes/summary';
+import Details from './nodes/details';
+
+import Bold from './marks/bold';
+import Italic from './marks/italic';
+import Strike from './marks/strike';
+import InlineDiff from './marks/inline_diff';
+
+import Link from './marks/link';
+import Code from './marks/code';
+import MathMark from './marks/math';
+import InlineHTML from './marks/inline_html';
+
+// The filters referenced in lib/banzai/pipeline/gfm_pipeline.rb transform
+// GitLab Flavored Markdown (GFM) to HTML.
+// The nodes and marks referenced here transform that same HTML to GFM to be copied to the clipboard.
+// Every filter in lib/banzai/pipeline/gfm_pipeline.rb that generates HTML
+// from GFM should have a node or mark here.
+// The GFM-to-HTML-to-GFM cycle is tested in spec/features/copy_as_gfm_spec.rb.
+
+export default [
+  new Doc(),
+  new Paragraph(),
+  new Text(),
+
+  new Blockquote(),
+  new CodeBlock(),
+  new HardBreak(),
+  new Heading({ maxLevel: 6 }),
+  new HorizontalRule(),
+  new Image(),
+
+  new Table(),
+  new TableHead(),
+  new TableBody(),
+  new TableHeaderRow(),
+  new TableRow(),
+  new TableCell(),
+
+  new Emoji(),
+  new Reference(),
+
+  new TableOfContents(),
+  new Video(),
+
+  new BulletList(),
+  new OrderedList(),
+  new ListItem(),
+
+  new DescriptionList(),
+  new DescriptionTerm(),
+  new DescriptionDetails(),
+
+  new TaskList(),
+  new OrderedTaskList(),
+  new TaskListItem(),
+
+  new Summary(),
+  new Details(),
+
+  new Bold(),
+  new Italic(),
+  new Strike(),
+  new InlineDiff(),
+
+  new Link(),
+  new Code(),
+  new MathMark(),
+  new InlineHTML(),
+];
diff --git a/app/assets/javascripts/behaviors/markdown/marks/bold.js b/app/assets/javascripts/behaviors/markdown/marks/bold.js
new file mode 100644
index 00000000000..b537954c1cb
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/marks/bold.js
@@ -0,0 +1,11 @@
+/* eslint-disable class-methods-use-this */
+
+import { Bold as BaseBold } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Bold extends BaseBold {
+  get toMarkdown() {
+    return defaultMarkdownSerializer.marks.strong;
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/marks/code.js b/app/assets/javascripts/behaviors/markdown/marks/code.js
new file mode 100644
index 00000000000..a760ee80dd0
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/marks/code.js
@@ -0,0 +1,11 @@
+/* eslint-disable class-methods-use-this */
+
+import { Code as BaseCode } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Code extends BaseCode {
+  get toMarkdown() {
+    return defaultMarkdownSerializer.marks.code;
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/marks/inline_diff.js b/app/assets/javascripts/behaviors/markdown/marks/inline_diff.js
new file mode 100644
index 00000000000..ce425e80cd3
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/marks/inline_diff.js
@@ -0,0 +1,41 @@
+/* eslint-disable class-methods-use-this */
+
+import { Mark } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::InlineDiffFilter
+export default class InlineDiff extends Mark {
+  get name() {
+    return 'inline_diff';
+  }
+
+  get schema() {
+    return {
+      attrs: {
+        addition: {
+          default: true,
+        },
+      },
+      parseDOM: [
+        { tag: 'span.idiff.addition', attrs: { addition: true } },
+        { tag: 'span.idiff.deletion', attrs: { addition: false } },
+      ],
+      toDOM: node => [
+        'span',
+        { class: `idiff left right ${node.attrs.addition ? 'addition' : 'deletion'}` },
+        0,
+      ],
+    };
+  }
+
+  get toMarkdown() {
+    return {
+      mixable: true,
+      open(state, mark) {
+        return mark.attrs.addition ? '{+' : '{-';
+      },
+      close(state, mark) {
+        return mark.attrs.addition ? '+}' : '-}';
+      },
+    };
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/marks/inline_html.js b/app/assets/javascripts/behaviors/markdown/marks/inline_html.js
new file mode 100644
index 00000000000..ebed8698e21
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/marks/inline_html.js
@@ -0,0 +1,46 @@
+/* eslint-disable class-methods-use-this */
+
+import { Mark } from 'tiptap';
+import _ from 'underscore';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class InlineHTML extends Mark {
+  get name() {
+    return 'inline_html';
+  }
+
+  get schema() {
+    return {
+      excludes: '',
+      attrs: {
+        tag: {},
+        title: { default: null },
+      },
+      parseDOM: [
+        {
+          tag: 'sup, sub, kbd, q, samp, var',
+          getAttrs: el => ({ tag: el.nodeName.toLowerCase() }),
+        },
+        {
+          tag: 'abbr',
+          getAttrs: el => ({ tag: 'abbr', title: el.getAttribute('title') }),
+        },
+      ],
+      toDOM: node => [node.attrs.tag, { title: node.attrs.title }, 0],
+    };
+  }
+
+  get toMarkdown() {
+    return {
+      mixable: true,
+      open(state, mark) {
+        return `<${mark.attrs.tag}${
+          mark.attrs.title ? ` title="${state.esc(_.escape(mark.attrs.title))}"` : ''
+        }>`;
+      },
+      close(state, mark) {
+        return `</${mark.attrs.tag}>`;
+      },
+    };
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/marks/italic.js b/app/assets/javascripts/behaviors/markdown/marks/italic.js
new file mode 100644
index 00000000000..44b35c97739
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/marks/italic.js
@@ -0,0 +1,11 @@
+/* eslint-disable class-methods-use-this */
+
+import { Italic as BaseItalic } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Italic extends BaseItalic {
+  get toMarkdown() {
+    return defaultMarkdownSerializer.marks.em;
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/marks/link.js b/app/assets/javascripts/behaviors/markdown/marks/link.js
new file mode 100644
index 00000000000..5c23d6a5ceb
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/marks/link.js
@@ -0,0 +1,21 @@
+/* eslint-disable class-methods-use-this */
+
+import { Link as BaseLink } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Link extends BaseLink {
+  get toMarkdown() {
+    return {
+      mixable: true,
+      open(state, mark, parent, index) {
+        const open = defaultMarkdownSerializer.marks.link.open(state, mark, parent, index);
+        return open === '<' ? '' : open;
+      },
+      close(state, mark, parent, index) {
+        const close = defaultMarkdownSerializer.marks.link.close(state, mark, parent, index);
+        return close === '>' ? '' : close;
+      },
+    };
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/marks/math.js b/app/assets/javascripts/behaviors/markdown/marks/math.js
new file mode 100644
index 00000000000..e582fb18f15
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/marks/math.js
@@ -0,0 +1,41 @@
+/* eslint-disable class-methods-use-this */
+
+import { Mark } from 'tiptap';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MathFilter
+export default class MathMark extends Mark {
+  get name() {
+    return 'math';
+  }
+
+  get schema() {
+    return {
+      parseDOM: [
+        // Matches HTML generated by Banzai::Filter::MathFilter
+        {
+          tag: 'code.code.math[data-math-style=inline]',
+          priority: 51,
+        },
+        // Matches HTML after being transformed by app/assets/javascripts/behaviors/markdown/render_math.js
+        {
+          tag: 'span.katex',
+          contentElement: 'annotation[encoding="application/x-tex"]',
+        },
+      ],
+      toDOM: () => ['code', { class: 'code math', 'data-math-style': 'inline' }, 0],
+    };
+  }
+
+  get toMarkdown() {
+    return {
+      escape: false,
+      open(state, mark, parent, index) {
+        return `$${defaultMarkdownSerializer.marks.code.open(state, mark, parent, index)}`;
+      },
+      close(state, mark, parent, index) {
+        return `${defaultMarkdownSerializer.marks.code.close(state, mark, parent, index)}$`;
+      },
+    };
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/marks/strike.js b/app/assets/javascripts/behaviors/markdown/marks/strike.js
new file mode 100644
index 00000000000..c2951a40a4b
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/marks/strike.js
@@ -0,0 +1,15 @@
+/* eslint-disable class-methods-use-this */
+
+import { Strike as BaseStrike } from 'tiptap-extensions';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Strike extends BaseStrike {
+  get toMarkdown() {
+    return {
+      open: '~~',
+      close: '~~',
+      mixable: true,
+      expelEnclosingWhitespace: true,
+    };
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/blockquote.js b/app/assets/javascripts/behaviors/markdown/nodes/blockquote.js
new file mode 100644
index 00000000000..b0bc8f79643
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/blockquote.js
@@ -0,0 +1,13 @@
+/* eslint-disable class-methods-use-this */
+
+import { Blockquote as BaseBlockquote } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Blockquote extends BaseBlockquote {
+  toMarkdown(state, node) {
+    if (!node.childCount) return;
+
+    defaultMarkdownSerializer.nodes.blockquote(state, node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/bullet_list.js b/app/assets/javascripts/behaviors/markdown/nodes/bullet_list.js
new file mode 100644
index 00000000000..3b0792e1af8
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/bullet_list.js
@@ -0,0 +1,11 @@
+/* eslint-disable class-methods-use-this */
+
+import { BulletList as BaseBulletList } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class BulletList extends BaseBulletList {
+  toMarkdown(state, node) {
+    defaultMarkdownSerializer.nodes.bullet_list(state, node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/code_block.js b/app/assets/javascripts/behaviors/markdown/nodes/code_block.js
new file mode 100644
index 00000000000..b9b894b3348
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/code_block.js
@@ -0,0 +1,79 @@
+/* eslint-disable class-methods-use-this */
+
+import { CodeBlock as BaseCodeBlock } from 'tiptap-extensions';
+
+const PLAINTEXT_LANG = 'plaintext';
+
+// Transforms generated HTML back to GFM for:
+// - Banzai::Filter::SyntaxHighlightFilter
+// - Banzai::Filter::MathFilter
+// - Banzai::Filter::MermaidFilter
+export default class CodeBlock extends BaseCodeBlock {
+  get schema() {
+    return {
+      content: 'text*',
+      marks: '',
+      group: 'block',
+      code: true,
+      defining: true,
+      attrs: {
+        lang: { default: PLAINTEXT_LANG },
+      },
+      parseDOM: [
+        // Matches HTML generated by Banzai::Filter::SyntaxHighlightFilter, Banzai::Filter::MathFilter or Banzai::Filter::MermaidFilter
+        {
+          tag: 'pre.code.highlight',
+          preserveWhitespace: 'full',
+          getAttrs: el => {
+            const lang = el.getAttribute('lang');
+            if (!lang || lang === '') return {};
+
+            return { lang };
+          },
+        },
+        // Matches HTML generated by Banzai::Filter::MathFilter,
+        // after being transformed by app/assets/javascripts/behaviors/markdown/render_math.js
+        {
+          tag: 'span.katex-display',
+          preserveWhitespace: 'full',
+          contentElement: 'annotation[encoding="application/x-tex"]',
+          attrs: { lang: 'math' },
+        },
+        // Matches HTML generated by Banzai::Filter::MathFilter,
+        // after being transformed by app/assets/javascripts/behaviors/markdown/render_mermaid.js
+        {
+          tag: 'svg.mermaid',
+          preserveWhitespace: 'full',
+          contentElement: 'text.source',
+          attrs: { lang: 'mermaid' },
+        },
+      ],
+      toDOM: node => ['pre', { class: 'code highlight', lang: node.attrs.lang }, ['code', 0]],
+    };
+  }
+
+  toMarkdown(state, node) {
+    if (!node.childCount) return;
+
+    const {
+      textContent: text,
+      attrs: { lang },
+    } = node;
+
+    // Prefixes lines with 4 spaces if the code contains a line that starts with triple backticks
+    if (lang === PLAINTEXT_LANG && text.match(/^```/gm)) {
+      state.wrapBlock('    ', null, node, () => state.text(text, false));
+      return;
+    }
+
+    state.write('```');
+    if (lang !== PLAINTEXT_LANG) state.write(lang);
+
+    state.ensureNewLine();
+    state.text(text, false);
+    state.ensureNewLine();
+
+    state.write('```');
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/description_details.js b/app/assets/javascripts/behaviors/markdown/nodes/description_details.js
new file mode 100644
index 00000000000..a4451d8ce8d
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/description_details.js
@@ -0,0 +1,28 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class DescriptionDetails extends Node {
+  get name() {
+    return 'description_details';
+  }
+
+  get schema() {
+    return {
+      content: 'text*',
+      marks: '',
+      defining: true,
+      parseDOM: [{ tag: 'dd' }],
+      toDOM: () => ['dd', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.flushClose(1);
+    state.write('<dd>');
+    state.text(node.textContent, false);
+    state.write('</dd>');
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/description_list.js b/app/assets/javascripts/behaviors/markdown/nodes/description_list.js
new file mode 100644
index 00000000000..6aa1aca29d7
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/description_list.js
@@ -0,0 +1,28 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class DescriptionList extends Node {
+  get name() {
+    return 'description_list';
+  }
+
+  get schema() {
+    return {
+      content: '(description_term+ description_details+)+',
+      group: 'block',
+      parseDOM: [{ tag: 'dl' }],
+      toDOM: () => ['dl', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.write('<dl>\n');
+    state.wrapBlock('  ', null, node, () => state.renderContent(node));
+    state.flushClose(1);
+    state.ensureNewLine();
+    state.write('</dl>');
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/description_term.js b/app/assets/javascripts/behaviors/markdown/nodes/description_term.js
new file mode 100644
index 00000000000..89057ec6444
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/description_term.js
@@ -0,0 +1,28 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class DescriptionTerm extends Node {
+  get name() {
+    return 'description_term';
+  }
+
+  get schema() {
+    return {
+      content: 'text*',
+      marks: '',
+      defining: true,
+      parseDOM: [{ tag: 'dt' }],
+      toDOM: () => ['dt', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.flushClose(state.closed && state.closed.type === node.type ? 1 : 2);
+    state.write('<dt>');
+    state.text(node.textContent, false);
+    state.write('</dt>');
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/details.js b/app/assets/javascripts/behaviors/markdown/nodes/details.js
new file mode 100644
index 00000000000..1c40dbb8168
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/details.js
@@ -0,0 +1,28 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Details extends Node {
+  get name() {
+    return 'details';
+  }
+
+  get schema() {
+    return {
+      content: 'summary block*',
+      group: 'block',
+      parseDOM: [{ tag: 'details' }],
+      toDOM: () => ['details', { open: true, onclick: 'return false', tabindex: '-1' }, 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.write('<details>\n');
+    state.renderContent(node);
+    state.flushClose(1);
+    state.ensureNewLine();
+    state.write('</details>');
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/doc.js b/app/assets/javascripts/behaviors/markdown/nodes/doc.js
new file mode 100644
index 00000000000..88b16fd85da
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/doc.js
@@ -0,0 +1,15 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+export default class Doc extends Node {
+  get name() {
+    return 'doc';
+  }
+
+  get schema() {
+    return {
+      content: 'block+',
+    };
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/emoji.js b/app/assets/javascripts/behaviors/markdown/nodes/emoji.js
new file mode 100644
index 00000000000..a7cc3e828f5
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/emoji.js
@@ -0,0 +1,41 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::EmojiFilter
+export default class Emoji extends Node {
+  get name() {
+    return 'emoji';
+  }
+
+  get schema() {
+    return {
+      inline: true,
+      group: 'inline',
+      attrs: {
+        name: {},
+        title: {},
+        moji: {},
+      },
+      parseDOM: [
+        {
+          tag: 'gl-emoji',
+          getAttrs: el => ({
+            name: el.dataset.name,
+            title: el.getAttribute('title'),
+            moji: el.textContent,
+          }),
+        },
+      ],
+      toDOM: node => [
+        'gl-emoji',
+        { 'data-name': node.attrs.name, title: node.attrs.title },
+        node.attrs.moji,
+      ],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.write(`:${node.attrs.name}:`);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/hard_break.js b/app/assets/javascripts/behaviors/markdown/nodes/hard_break.js
new file mode 100644
index 00000000000..59e5d8ab3e2
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/hard_break.js
@@ -0,0 +1,10 @@
+/* eslint-disable class-methods-use-this */
+
+import { HardBreak as BaseHardBreak } from 'tiptap-extensions';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class HardBreak extends BaseHardBreak {
+  toMarkdown(state) {
+    if (!state.atBlank()) state.write('  \n');
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/heading.js b/app/assets/javascripts/behaviors/markdown/nodes/heading.js
new file mode 100644
index 00000000000..fec8608cf5d
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/heading.js
@@ -0,0 +1,13 @@
+/* eslint-disable class-methods-use-this */
+
+import { Heading as BaseHeading } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Heading extends BaseHeading {
+  toMarkdown(state, node) {
+    if (!node.childCount) return;
+
+    defaultMarkdownSerializer.nodes.heading(state, node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/horizontal_rule.js b/app/assets/javascripts/behaviors/markdown/nodes/horizontal_rule.js
new file mode 100644
index 00000000000..695c7160bde
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/horizontal_rule.js
@@ -0,0 +1,11 @@
+/* eslint-disable class-methods-use-this */
+
+import { HorizontalRule as BaseHorizontalRule } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class HorizontalRule extends BaseHorizontalRule {
+  toMarkdown(state, node) {
+    defaultMarkdownSerializer.nodes.horizontal_rule(state, node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/image.js b/app/assets/javascripts/behaviors/markdown/nodes/image.js
new file mode 100644
index 00000000000..c225a5ed876
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/image.js
@@ -0,0 +1,52 @@
+/* eslint-disable class-methods-use-this */
+
+import { Image as BaseImage } from 'tiptap-extensions';
+import { placeholderImage } from '~/lazy_loader';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+export default class Image extends BaseImage {
+  get schema() {
+    return {
+      attrs: {
+        src: {},
+        alt: {
+          default: null,
+        },
+        title: {
+          default: null,
+        },
+      },
+      group: 'inline',
+      inline: true,
+      draggable: true,
+      parseDOM: [
+        // Matches HTML generated by Banzai::Filter::ImageLinkFilter
+        {
+          tag: 'a.no-attachment-icon',
+          priority: 51,
+          skip: true,
+        },
+        // Matches HTML generated by Banzai::Filter::ImageLazyLoadFilter
+        {
+          tag: 'img[src]',
+          getAttrs: el => {
+            const imageSrc = el.src;
+            const imageUrl =
+              imageSrc && imageSrc !== placeholderImage ? imageSrc : el.dataset.src || '';
+
+            return {
+              src: imageUrl,
+              title: el.getAttribute('title'),
+              alt: el.getAttribute('alt'),
+            };
+          },
+        },
+      ],
+      toDOM: node => ['img', node.attrs],
+    };
+  }
+
+  toMarkdown(state, node) {
+    defaultMarkdownSerializer.nodes.image(state, node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/list_item.js b/app/assets/javascripts/behaviors/markdown/nodes/list_item.js
new file mode 100644
index 00000000000..4237637ed9a
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/list_item.js
@@ -0,0 +1,11 @@
+/* eslint-disable class-methods-use-this */
+
+import { ListItem as BaseListItem } from 'tiptap-extensions';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class ListItem extends BaseListItem {
+  toMarkdown(state, node) {
+    defaultMarkdownSerializer.nodes.list_item(state, node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/ordered_list.js b/app/assets/javascripts/behaviors/markdown/nodes/ordered_list.js
new file mode 100644
index 00000000000..4c1542d14ea
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/ordered_list.js
@@ -0,0 +1,10 @@
+/* eslint-disable class-methods-use-this */
+
+import { OrderedList as BaseOrderedList } from 'tiptap-extensions';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class OrderedList extends BaseOrderedList {
+  toMarkdown(state, node) {
+    state.renderList(node, '   ', () => '1. ');
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/ordered_task_list.js b/app/assets/javascripts/behaviors/markdown/nodes/ordered_task_list.js
new file mode 100644
index 00000000000..25c4976a1bc
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/ordered_task_list.js
@@ -0,0 +1,28 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::TaskListFilter
+export default class OrderedTaskList extends Node {
+  get name() {
+    return 'ordered_task_list';
+  }
+
+  get schema() {
+    return {
+      group: 'block',
+      content: '(task_list_item|list_item)+',
+      parseDOM: [
+        {
+          priority: 51,
+          tag: 'ol.task-list',
+        },
+      ],
+      toDOM: () => ['ol', { class: 'task-list' }, 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.renderList(node, '   ', () => '1. ');
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/paragraph.js b/app/assets/javascripts/behaviors/markdown/nodes/paragraph.js
new file mode 100644
index 00000000000..dec3207b1bb
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/paragraph.js
@@ -0,0 +1,24 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Paragraph extends Node {
+  get name() {
+    return 'paragraph';
+  }
+
+  get schema() {
+    return {
+      content: 'inline*',
+      group: 'block',
+      parseDOM: [{ tag: 'p' }],
+      toDOM: () => ['p', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    defaultMarkdownSerializer.nodes.paragraph(state, node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/reference.js b/app/assets/javascripts/behaviors/markdown/nodes/reference.js
new file mode 100644
index 00000000000..5d6bbeca833
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/reference.js
@@ -0,0 +1,52 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::ReferenceFilter and subclasses
+export default class Reference extends Node {
+  get name() {
+    return 'reference';
+  }
+
+  get schema() {
+    return {
+      inline: true,
+      group: 'inline',
+      atom: true,
+      attrs: {
+        className: {},
+        referenceType: {},
+        originalText: { default: null },
+        href: {},
+        text: {},
+      },
+      parseDOM: [
+        {
+          tag: 'a.gfm:not([data-link=true])',
+          priority: 51,
+          getAttrs: el => ({
+            className: el.className,
+            referenceType: el.dataset.referenceType,
+            originalText: el.dataset.original,
+            href: el.getAttribute('href'),
+            text: el.textContent,
+          }),
+        },
+      ],
+      toDOM: node => [
+        'a',
+        {
+          class: node.attrs.className,
+          href: node.attrs.href,
+          'data-reference-type': node.attrs.referenceType,
+          'data-original': node.attrs.originalText,
+        },
+        node.attrs.text,
+      ],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.write(node.attrs.originalText || node.attrs.text);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/summary.js b/app/assets/javascripts/behaviors/markdown/nodes/summary.js
new file mode 100644
index 00000000000..2e36e316d71
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/summary.js
@@ -0,0 +1,27 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Summary extends Node {
+  get name() {
+    return 'summary';
+  }
+
+  get schema() {
+    return {
+      content: 'text*',
+      marks: '',
+      defining: true,
+      parseDOM: [{ tag: 'summary' }],
+      toDOM: () => ['summary', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.write('<summary>');
+    state.text(node.textContent, false);
+    state.write('</summary>');
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/table.js b/app/assets/javascripts/behaviors/markdown/nodes/table.js
new file mode 100644
index 00000000000..a7fcb9227cd
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/table.js
@@ -0,0 +1,25 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class Table extends Node {
+  get name() {
+    return 'table';
+  }
+
+  get schema() {
+    return {
+      content: 'table_head table_body',
+      group: 'block',
+      isolating: true,
+      parseDOM: [{ tag: 'table' }],
+      toDOM: () => ['table', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.renderContent(node);
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/table_body.js b/app/assets/javascripts/behaviors/markdown/nodes/table_body.js
new file mode 100644
index 00000000000..403556dc0c8
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/table_body.js
@@ -0,0 +1,24 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class TableBody extends Node {
+  get name() {
+    return 'table_body';
+  }
+
+  get schema() {
+    return {
+      content: 'table_row+',
+      parseDOM: [{ tag: 'tbody' }],
+      toDOM: () => ['tbody', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.flushClose(1);
+    state.renderContent(node);
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/table_cell.js b/app/assets/javascripts/behaviors/markdown/nodes/table_cell.js
new file mode 100644
index 00000000000..c63bfe10e39
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/table_cell.js
@@ -0,0 +1,35 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class TableCell extends Node {
+  get name() {
+    return 'table_cell';
+  }
+
+  get schema() {
+    return {
+      attrs: {
+        header: { default: false },
+        align: { default: null },
+      },
+      content: 'inline*',
+      isolating: true,
+      parseDOM: [
+        {
+          tag: 'td, th',
+          getAttrs: el => ({
+            header: el.tagName === 'TH',
+            align: el.getAttribute('align') || el.style.textAlign,
+          }),
+        },
+      ],
+      toDOM: node => [node.attrs.header ? 'th' : 'td', { align: node.attrs.align }, 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.renderInline(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/table_head.js b/app/assets/javascripts/behaviors/markdown/nodes/table_head.js
new file mode 100644
index 00000000000..4cb94bf088c
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/table_head.js
@@ -0,0 +1,24 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class TableHead extends Node {
+  get name() {
+    return 'table_head';
+  }
+
+  get schema() {
+    return {
+      content: 'table_header_row',
+      parseDOM: [{ tag: 'thead' }],
+      toDOM: () => ['thead', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.flushClose(1);
+    state.renderContent(node);
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/table_header_row.js b/app/assets/javascripts/behaviors/markdown/nodes/table_header_row.js
new file mode 100644
index 00000000000..e7eee636402
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/table_header_row.js
@@ -0,0 +1,43 @@
+/* eslint-disable class-methods-use-this */
+
+import TableRow from './table_row';
+
+const CENTER_ALIGN = 'center';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class TableHeaderRow extends TableRow {
+  get name() {
+    return 'table_header_row';
+  }
+
+  get schema() {
+    return {
+      content: 'table_cell+',
+      parseDOM: [
+        {
+          tag: 'thead tr',
+          priority: 51,
+        },
+      ],
+      toDOM: () => ['tr', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    const cellWidths = super.toMarkdown(state, node);
+
+    state.flushClose(1);
+
+    state.write('|');
+    node.forEach((cell, _, i) => {
+      if (i) state.write('|');
+
+      state.write(cell.attrs.align === CENTER_ALIGN ? ':' : '-');
+      state.write(state.repeat('-', cellWidths[i]));
+      state.write(cell.attrs.align === CENTER_ALIGN || cell.attrs.align === 'right' ? ':' : '-');
+    });
+    state.write('|');
+
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/table_of_contents.js b/app/assets/javascripts/behaviors/markdown/nodes/table_of_contents.js
new file mode 100644
index 00000000000..20c7fa8a9ab
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/table_of_contents.js
@@ -0,0 +1,33 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::TableOfContentsFilter
+export default class TableOfContents extends Node {
+  get name() {
+    return 'table_of_contents';
+  }
+
+  get schema() {
+    return {
+      group: 'block',
+      atom: true,
+      parseDOM: [
+        {
+          tag: 'ul.section-nav',
+          priority: 51,
+        },
+        {
+          tag: 'p.table-of-contents',
+          priority: 51,
+        },
+      ],
+      toDOM: () => ['p', { class: 'table-of-contents' }, 'Table of Contents'],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.write('[[_TOC_]]');
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/table_row.js b/app/assets/javascripts/behaviors/markdown/nodes/table_row.js
new file mode 100644
index 00000000000..5852502773a
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/table_row.js
@@ -0,0 +1,38 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class TableRow extends Node {
+  get name() {
+    return 'table_row';
+  }
+
+  get schema() {
+    return {
+      content: 'table_cell+',
+      parseDOM: [{ tag: 'tr' }],
+      toDOM: () => ['tr', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    const cellWidths = [];
+
+    state.flushClose(1);
+
+    state.write('| ');
+    node.forEach((cell, _, i) => {
+      if (i) state.write(' | ');
+
+      const { length } = state.out;
+      state.render(cell, node, i);
+      cellWidths.push(state.out.length - length);
+    });
+    state.write(' |');
+
+    state.closeBlock(node);
+
+    return cellWidths;
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/task_list.js b/app/assets/javascripts/behaviors/markdown/nodes/task_list.js
new file mode 100644
index 00000000000..ab33bc21502
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/task_list.js
@@ -0,0 +1,28 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::TaskListFilter
+export default class TaskList extends Node {
+  get name() {
+    return 'task_list';
+  }
+
+  get schema() {
+    return {
+      group: 'block',
+      content: '(task_list_item|list_item)+',
+      parseDOM: [
+        {
+          priority: 51,
+          tag: 'ul.task-list',
+        },
+      ],
+      toDOM: () => ['ul', { class: 'task-list' }, 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.renderList(node, '  ', () => '* ');
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/task_list_item.js b/app/assets/javascripts/behaviors/markdown/nodes/task_list_item.js
new file mode 100644
index 00000000000..d0ee7333d5e
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/task_list_item.js
@@ -0,0 +1,49 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::TaskListFilter
+export default class TaskListItem extends Node {
+  get name() {
+    return 'task_list_item';
+  }
+
+  get schema() {
+    return {
+      attrs: {
+        done: {
+          default: false,
+        },
+      },
+      defining: true,
+      draggable: false,
+      content: 'paragraph block*',
+      parseDOM: [
+        {
+          priority: 51,
+          tag: 'li.task-list-item',
+          getAttrs: el => {
+            const checkbox = el.querySelector('input[type=checkbox].task-list-item-checkbox');
+            return { done: checkbox && checkbox.checked };
+          },
+        },
+      ],
+      toDOM(node) {
+        return [
+          'li',
+          { class: 'task-list-item' },
+          [
+            'input',
+            { type: 'checkbox', class: 'task-list-item-checkbox', checked: node.attrs.done },
+          ],
+          ['div', { class: 'todo-content' }, 0],
+        ];
+      },
+    };
+  }
+
+  toMarkdown(state, node) {
+    state.write(`[${node.attrs.done ? 'x' : ' '}] `);
+    state.renderContent(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/text.js b/app/assets/javascripts/behaviors/markdown/nodes/text.js
new file mode 100644
index 00000000000..84838c14999
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/text.js
@@ -0,0 +1,20 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+export default class Text extends Node {
+  get name() {
+    return 'text';
+  }
+
+  get schema() {
+    return {
+      group: 'inline',
+    };
+  }
+
+  toMarkdown(state, node) {
+    defaultMarkdownSerializer.nodes.text(state, node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/video.js b/app/assets/javascripts/behaviors/markdown/nodes/video.js
new file mode 100644
index 00000000000..516f983397d
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/video.js
@@ -0,0 +1,54 @@
+/* eslint-disable class-methods-use-this */
+
+import { Node } from 'tiptap';
+import { defaultMarkdownSerializer } from 'prosemirror-markdown';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::VideoLinkFilter
+export default class Video extends Node {
+  get name() {
+    return 'video';
+  }
+
+  get schema() {
+    return {
+      attrs: {
+        src: {},
+        alt: {
+          default: null,
+        },
+      },
+      group: 'block',
+      draggable: true,
+      parseDOM: [
+        {
+          tag: '.video-container',
+          skip: true,
+        },
+        {
+          tag: '.video-container p',
+          priority: 51,
+          ignore: true,
+        },
+        {
+          tag: 'video[src]',
+          getAttrs: el => ({ src: el.getAttribute('src'), alt: el.dataset.title }),
+        },
+      ],
+      toDOM: node => [
+        'video',
+        {
+          src: node.attrs.src,
+          width: '400',
+          controls: true,
+          'data-setup': '{}',
+          'data-title': node.attrs.alt,
+        },
+      ],
+    };
+  }
+
+  toMarkdown(state, node) {
+    defaultMarkdownSerializer.nodes.image(state, node);
+    state.closeBlock(node);
+  }
+}
diff --git a/app/assets/javascripts/behaviors/markdown/schema.js b/app/assets/javascripts/behaviors/markdown/schema.js
new file mode 100644
index 00000000000..163182ab778
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/schema.js
@@ -0,0 +1,24 @@
+import { Schema } from 'prosemirror-model';
+import editorExtensions from './editor_extensions';
+
+const nodes = editorExtensions
+  .filter(extension => extension.type === 'node')
+  .reduce(
+    (ns, { name, schema }) => ({
+      ...ns,
+      [name]: schema,
+    }),
+    {},
+  );
+
+const marks = editorExtensions
+  .filter(extension => extension.type === 'mark')
+  .reduce(
+    (ms, { name, schema }) => ({
+      ...ms,
+      [name]: schema,
+    }),
+    {},
+  );
+
+export default new Schema({ nodes, marks });
diff --git a/app/assets/javascripts/behaviors/markdown/serializer.js b/app/assets/javascripts/behaviors/markdown/serializer.js
new file mode 100644
index 00000000000..70dbd8bd206
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/serializer.js
@@ -0,0 +1,24 @@
+import { MarkdownSerializer } from 'prosemirror-markdown';
+import editorExtensions from './editor_extensions';
+
+const nodes = editorExtensions
+  .filter(extension => extension.type === 'node')
+  .reduce(
+    (ns, { name, toMarkdown }) => ({
+      ...ns,
+      [name]: toMarkdown,
+    }),
+    {},
+  );
+
+const marks = editorExtensions
+  .filter(extension => extension.type === 'mark')
+  .reduce(
+    (ms, { name, toMarkdown }) => ({
+      ...ms,
+      [name]: toMarkdown,
+    }),
+    {},
+  );
+
+export default new MarkdownSerializer(nodes, marks);
diff --git a/app/assets/javascripts/behaviors/shortcuts/shortcuts_issuable.js b/app/assets/javascripts/behaviors/shortcuts/shortcuts_issuable.js
index 2918e1486a7..0eb067d4963 100644
--- a/app/assets/javascripts/behaviors/shortcuts/shortcuts_issuable.js
+++ b/app/assets/javascripts/behaviors/shortcuts/shortcuts_issuable.js
@@ -1,6 +1,5 @@
 import $ from 'jquery';
 import Mousetrap from 'mousetrap';
-import _ from 'underscore';
 import Sidebar from '../../right_sidebar';
 import Shortcuts from './shortcuts';
 import { CopyAsGFM } from '../markdown/copy_as_gfm';
@@ -63,18 +62,18 @@ export default class ShortcutsIssuable extends Shortcuts {
     }
 
     const el = CopyAsGFM.transformGFMSelection(documentFragment.cloneNode(true));
-    const selected = CopyAsGFM.nodeToGFM(el);
+    const blockquoteEl = document.createElement('blockquote');
+    blockquoteEl.appendChild(el);
+    const text = CopyAsGFM.nodeToGFM(blockquoteEl);
 
-    if (selected.trim() === '') {
+    if (text.trim() === '') {
       return false;
     }
 
-    const quote = _.map(selected.split('\n'), val => `${`> ${val}`.trim()}\n`);
-
     // If replyField already has some content, add a newline before our quote
     const separator = ($replyField.val().trim() !== '' && '\n\n') || '';
     $replyField
-      .val((a, current) => `${current}${separator}${quote.join('')}\n`)
+      .val((a, current) => `${current}${separator}${text}\n\n`)
       .trigger('input')
       .trigger('change');
 
diff --git a/lib/banzai/filter/emoji_filter.rb b/lib/banzai/filter/emoji_filter.rb
index c87948a30bf..fa1690f73ad 100644
--- a/lib/banzai/filter/emoji_filter.rb
+++ b/lib/banzai/filter/emoji_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/emoji.js
 module Banzai
   module Filter
     # HTML filter that replaces :emoji: and unicode with images.
diff --git a/lib/banzai/filter/image_lazy_load_filter.rb b/lib/banzai/filter/image_lazy_load_filter.rb
index afaee70f351..d8b9eb29cf5 100644
--- a/lib/banzai/filter/image_lazy_load_filter.rb
+++ b/lib/banzai/filter/image_lazy_load_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/image.js
 module Banzai
   module Filter
     # HTML filter that moves the value of image `src` attributes to `data-src`
diff --git a/lib/banzai/filter/image_link_filter.rb b/lib/banzai/filter/image_link_filter.rb
index 884a94fb761..01237303c27 100644
--- a/lib/banzai/filter/image_link_filter.rb
+++ b/lib/banzai/filter/image_link_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/image.js
 module Banzai
   module Filter
     # HTML filter that wraps links around inline images.
diff --git a/lib/banzai/filter/inline_diff_filter.rb b/lib/banzai/filter/inline_diff_filter.rb
index e9ddc6e0e3d..5a1c0bee32d 100644
--- a/lib/banzai/filter/inline_diff_filter.rb
+++ b/lib/banzai/filter/inline_diff_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/marks/inline_diff.js
 module Banzai
   module Filter
     class InlineDiffFilter < HTML::Pipeline::Filter
diff --git a/lib/banzai/filter/math_filter.rb b/lib/banzai/filter/math_filter.rb
index 9d1bc3cf60c..8dd5a8979c8 100644
--- a/lib/banzai/filter/math_filter.rb
+++ b/lib/banzai/filter/math_filter.rb
@@ -2,6 +2,9 @@
 
 require 'uri'
 
+# Generated HTML is transformed back to GFM by:
+# - app/assets/javascripts/behaviors/markdown/marks/math.js
+# - app/assets/javascripts/behaviors/markdown/nodes/code_block.js
 module Banzai
   module Filter
     # HTML filter that adds class="code math" and removes the dollar sign in $`2+2`$.
diff --git a/lib/banzai/filter/mermaid_filter.rb b/lib/banzai/filter/mermaid_filter.rb
index 7c8b165a330..f0adb83af8a 100644
--- a/lib/banzai/filter/mermaid_filter.rb
+++ b/lib/banzai/filter/mermaid_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/code_block.js
 module Banzai
   module Filter
     class MermaidFilter < HTML::Pipeline::Filter
diff --git a/lib/banzai/filter/reference_filter.rb b/lib/banzai/filter/reference_filter.rb
index e5164e7f72a..42f9b3a689c 100644
--- a/lib/banzai/filter/reference_filter.rb
+++ b/lib/banzai/filter/reference_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/reference.js
 module Banzai
   module Filter
     # Base class for GitLab Flavored Markdown reference filters.
diff --git a/lib/banzai/filter/syntax_highlight_filter.rb b/lib/banzai/filter/syntax_highlight_filter.rb
index 18e5e9185de..bcf77861f10 100644
--- a/lib/banzai/filter/syntax_highlight_filter.rb
+++ b/lib/banzai/filter/syntax_highlight_filter.rb
@@ -3,6 +3,7 @@
 require 'rouge/plugins/common_mark'
 require 'rouge/plugins/redcarpet'
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/code_block.js
 module Banzai
   module Filter
     # HTML Filter to highlight fenced code blocks
diff --git a/lib/banzai/filter/table_of_contents_filter.rb b/lib/banzai/filter/table_of_contents_filter.rb
index c6d1e028eaa..f2ae17b44fa 100644
--- a/lib/banzai/filter/table_of_contents_filter.rb
+++ b/lib/banzai/filter/table_of_contents_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/table_of_contents.js
 module Banzai
   module Filter
     # HTML filter that adds an anchor child element to all Headers in a
diff --git a/lib/banzai/filter/task_list_filter.rb b/lib/banzai/filter/task_list_filter.rb
index ef35a49edcb..c6b402575cb 100644
--- a/lib/banzai/filter/task_list_filter.rb
+++ b/lib/banzai/filter/task_list_filter.rb
@@ -2,6 +2,10 @@
 
 require 'task_list/filter'
 
+# Generated HTML is transformed back to GFM by:
+# - app/assets/javascripts/behaviors/markdown/nodes/ordered_task_list.js
+# - app/assets/javascripts/behaviors/markdown/nodes/task_list.js
+# - app/assets/javascripts/behaviors/markdown/nodes/task_list_item.js
 module Banzai
   module Filter
     class TaskListFilter < TaskList::Filter
diff --git a/lib/banzai/filter/video_link_filter.rb b/lib/banzai/filter/video_link_filter.rb
index 0fb59c914c3..0fff104cf91 100644
--- a/lib/banzai/filter/video_link_filter.rb
+++ b/lib/banzai/filter/video_link_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/video.js
 module Banzai
   module Filter
     # Find every image that isn't already wrapped in an `a` tag, and that has
diff --git a/lib/banzai/pipeline/gfm_pipeline.rb b/lib/banzai/pipeline/gfm_pipeline.rb
index d860dad0b6c..30cafd11834 100644
--- a/lib/banzai/pipeline/gfm_pipeline.rb
+++ b/lib/banzai/pipeline/gfm_pipeline.rb
@@ -3,11 +3,11 @@
 module Banzai
   module Pipeline
     class GfmPipeline < BasePipeline
-      # These filters convert GitLab Flavored Markdown (GFM) to HTML.
-      # The handlers defined in app/assets/javascripts/behaviors/markdown/copy_as_gfm.js
-      # consequently convert that same HTML to GFM to be copied to the clipboard.
-      # Every filter that generates HTML from GFM should have a handler in
-      # app/assets/javascripts/behaviors/markdown/copy_as_gfm.js, in reverse order.
+      # These filters transform GitLab Flavored Markdown (GFM) to HTML.
+      # The nodes and marks referenced in app/assets/javascripts/behaviors/markdown/editor_extensions.js
+      # consequently transform that same HTML to GFM to be copied to the clipboard.
+      # Every filter that generates HTML from GFM should have a node or mark in
+      # app/assets/javascripts/behaviors/markdown/editor_extensions.js.
       # The GFM-to-HTML-to-GFM cycle is tested in spec/features/copy_as_gfm_spec.rb.
       def self.filters
         @filters ||= FilterArray[
diff --git a/package.json b/package.json
index ef5c3511121..82c15f90745 100644
--- a/package.json
+++ b/package.json
@@ -85,6 +85,8 @@
     "pikaday": "^1.6.1",
     "popper.js": "^1.14.3",
     "prismjs": "^1.6.0",
+    "prosemirror-markdown": "^1.3.0",
+    "prosemirror-model": "^1.6.4",
     "raphael": "^2.2.7",
     "raven-js": "^3.22.1",
     "raw-loader": "^1.0.0",
@@ -101,6 +103,9 @@
     "three-orbit-controls": "^82.1.0",
     "three-stl-loader": "^1.0.4",
     "timeago.js": "^3.0.2",
+    "tiptap": "^1.8.0",
+    "tiptap-commands": "^1.4.0",
+    "tiptap-extensions": "^1.8.0",
     "underscore": "^1.9.0",
     "url-loader": "^1.1.2",
     "visibilityjs": "^1.2.4",
diff --git a/spec/features/markdown/copy_as_gfm_spec.rb b/spec/features/markdown/copy_as_gfm_spec.rb
index 05228e27963..92dee494b7e 100644
--- a/spec/features/markdown/copy_as_gfm_spec.rb
+++ b/spec/features/markdown/copy_as_gfm_spec.rb
@@ -19,9 +19,9 @@ describe 'Copy as GFM', :js do
       visit project_issue_path(@project, @feat.issue)
     end
 
-    # The filters referenced in lib/banzai/pipeline/gfm_pipeline.rb convert GitLab Flavored Markdown (GFM) to HTML.
-    # The handlers defined in app/assets/javascripts/behaviors/markdown/copy_as_gfm.js consequently convert that same HTML to GFM.
-    # To make sure these filters and handlers are properly aligned, this spec tests the GFM-to-HTML-to-GFM cycle
+    # The filters referenced in lib/banzai/pipeline/gfm_pipeline.rb transform GitLab Flavored Markdown (GFM) to HTML.
+    # The nodes and marks referenced in app/assets/javascripts/behaviors/markdown/editor_extensions.js consequently transform that same HTML to GFM.
+    # To make sure these filters and nodes/marks are properly aligned, this spec tests the GFM-to-HTML-to-GFM cycle
     # by verifying (`html_to_gfm(gfm_to_html(gfm)) == gfm`) for a number of examples of GFM for every filter, using the `verify` helper.
 
     # These are all in a single `it` for performance reasons.
@@ -35,12 +35,15 @@ describe 'Copy as GFM', :js do
       verify(
         'a real world example from the gitlab-ce README',
 
-        <<-GFM.strip_heredoc
+        <<~GFM
           # GitLab
 
           [![Build status](https://gitlab.com/gitlab-org/gitlab-ce/badges/master/build.svg)](https://gitlab.com/gitlab-org/gitlab-ce/commits/master)
+
           [![CE coverage report](https://gitlab.com/gitlab-org/gitlab-ce/badges/master/coverage.svg?job=coverage)](https://gitlab-org.gitlab.io/gitlab-ce/coverage-ruby)
+
           [![Code Climate](https://codeclimate.com/github/gitlabhq/gitlabhq.svg)](https://codeclimate.com/github/gitlabhq/gitlabhq)
+
           [![Core Infrastructure Initiative Best Practices](https://bestpractices.coreinfrastructure.org/projects/42/badge)](https://bestpractices.coreinfrastructure.org/projects/42)
 
           ## Canonical source
@@ -51,27 +54,31 @@ describe 'Copy as GFM', :js do
 
           To see how GitLab looks please see the [features page on our website](https://about.gitlab.com/features/).
 
-          - Manage Git repositories with fine grained access controls that keep your code secure
+          * Manage Git repositories with fine grained access controls that keep your code secure
 
-          - Perform code reviews and enhance collaboration with merge requests
+          * Perform code reviews and enhance collaboration with merge requests
 
-          - Complete continuous integration (CI) and CD pipelines to builds, test, and deploy your applications
+          * Complete continuous integration (CI) and CD pipelines to builds, test, and deploy your applications
 
-          - Each project can also have an issue tracker, issue board, and a wiki
+          * Each project can also have an issue tracker, issue board, and a wiki
 
-          - Used by more than 100,000 organizations, GitLab is the most popular solution to manage Git repositories on-premises
+          * Used by more than 100,000 organizations, GitLab is the most popular solution to manage Git repositories on-premises
 
-          - Completely free and open source (MIT Expat license)
+          * Completely free and open source (MIT Expat license)
         GFM
       )
 
       aggregate_failures('an accidentally selected empty element') do
         gfm = '# Heading1'
 
-        html = <<-HTML.strip_heredoc
+        html = <<~HTML
           <h1>Heading1</h1>
 
           <h2></h2>
+
+          <blockquote></blockquote>
+
+          <pre class="code highlight"></pre>
         HTML
 
         output_gfm = html_to_gfm(html)
@@ -81,7 +88,7 @@ describe 'Copy as GFM', :js do
       aggregate_failures('an accidentally selected other element') do
         gfm = 'Test comment with **Markdown!**'
 
-        html = <<-HTML.strip_heredoc
+        html = <<~HTML
           <li class="note">
             <div class="md">
               <p>
@@ -107,10 +114,17 @@ describe 'Copy as GFM', :js do
       verify(
         'TaskListFilter',
 
-        '- [ ] Unchecked task',
-        '- [x] Checked task',
-        '1. [ ] Unchecked numbered task',
-        '1. [x] Checked numbered task'
+        <<~GFM,
+          * [ ] Unchecked task
+
+          * [x] Checked task
+        GFM
+
+        <<~GFM
+          1. [ ] Unchecked ordered task
+
+          1. [x] Checked ordered task
+        GFM
       )
 
       verify(
@@ -139,7 +153,16 @@ describe 'Copy as GFM', :js do
       verify(
         'TableOfContentsFilter',
 
-        '[[_TOC_]]'
+        <<~GFM,
+          [[_TOC_]]
+
+          # Heading 1
+
+          ## Heading 2
+        GFM
+
+        pipeline: :wiki,
+        project_wiki: @project.wiki
       )
 
       verify(
@@ -166,7 +189,7 @@ describe 'Copy as GFM', :js do
         '$`c = \pm\sqrt{a^2 + b^2}`$',
 
         # math block
-        <<-GFM.strip_heredoc
+        <<~GFM
           ```math
           c = \pm\sqrt{a^2 + b^2}
           ```
@@ -176,7 +199,7 @@ describe 'Copy as GFM', :js do
       aggregate_failures('MathFilter: math as transformed from HTML to KaTeX') do
         gfm = '$`c = \pm\sqrt{a^2 + b^2}`$'
 
-        html = <<-HTML.strip_heredoc
+        html = <<~HTML
           <span class="katex">
             <span class="katex-mathml">
               <math>
@@ -287,7 +310,7 @@ describe 'Copy as GFM', :js do
       verify(
         'MermaidFilter: mermaid as converted from GFM to HTML',
 
-        <<-GFM.strip_heredoc
+        <<~GFM
           ```mermaid
           graph TD;
             A-->B;
@@ -296,14 +319,14 @@ describe 'Copy as GFM', :js do
       )
 
       aggregate_failures('MermaidFilter: mermaid as transformed from HTML to SVG') do
-        gfm = <<-GFM.strip_heredoc
+        gfm = <<~GFM
           ```mermaid
           graph TD;
             A-->B;
           ```
         GFM
 
-        html = <<-HTML.strip_heredoc
+        html = <<~HTML
           <svg id="mermaidChart1" xmlns="http://www.w3.org/2000/svg" height="100%" viewBox="0 0 87.234375 174" style="max-width:87.234375px;" class="mermaid">
             <style>
               .mermaid {
@@ -371,8 +394,7 @@ describe 'Copy as GFM', :js do
               </g>
             </g>
             <text class="source" display="none">graph TD;
-            A--&gt;B;
-            </text>
+            A--&gt;B;</text>
           </svg>
         HTML
 
@@ -383,11 +405,18 @@ describe 'Copy as GFM', :js do
       verify(
         'SanitizationFilter',
 
-        <<-GFM.strip_heredoc
+        <<~GFM
         <sub>sub</sub>
 
         <dl>
           <dt>dt</dt>
+          <dt>dt</dt>
+          <dd>dd</dd>
+          <dd>dd</dd>
+
+          <dt>dt</dt>
+          <dt>dt</dt>
+          <dd>dd</dd>
           <dd>dd</dd>
         </dl>
 
@@ -399,30 +428,26 @@ describe 'Copy as GFM', :js do
 
         <var>var</var>
 
-        <ruby>ruby</ruby>
+        <abbr title="HyperText &quot;Markup&quot; Language">HTML</abbr>
 
-        <rt>rt</rt>
+        <details>
+        <summary>summary></summary>
 
-        <rp>rp</rp>
-
-        <abbr>abbr</abbr>
-
-        <summary>summary</summary>
-
-        <details>details</details>
+        details
+        </details>
         GFM
       )
 
       verify(
         'SanitizationFilter',
 
-        <<-GFM.strip_heredoc,
+        <<~GFM,
           ```
           Plain text
           ```
         GFM
 
-        <<-GFM.strip_heredoc,
+        <<~GFM,
           ```ruby
           def foo
             bar
@@ -430,11 +455,9 @@ describe 'Copy as GFM', :js do
           ```
         GFM
 
-        <<-GFM.strip_heredoc
+        <<~GFM
           Foo
 
-              This is an example of GFM
-
               ```js
               Code goes here
               ```
@@ -452,9 +475,8 @@ describe 'Copy as GFM', :js do
         '> Quote',
 
         # multiline quote
-        <<-GFM.strip_heredoc,
-          > Multiline
-          > Quote
+        <<~GFM,
+          > Multiline Quote
           >
           > With multiple paragraphs
         GFM
@@ -465,48 +487,58 @@ describe 'Copy as GFM', :js do
 
         '[Link](https://example.com)',
 
-        '- List item',
+        <<~GFM,
+          * List item
+
+          * List item 2
+        GFM
 
         # multiline list item
-        <<-GFM.strip_heredoc,
-          - Multiline
-              List item
+        <<~GFM,
+          * Multiline
+
+            List item
         GFM
 
         # nested lists
-        <<-GFM.strip_heredoc,
-          - Nested
+        <<~GFM,
+          * Nested
 
-              - Lists
+            * Lists
         GFM
 
         # list with blockquote
-        <<-GFM.strip_heredoc,
-          - List
+        <<~GFM,
+          * List
 
-              > Blockquote
+            > Blockquote
         GFM
 
-        '1. Numbered list item',
+        <<~GFM,
+          1. Ordered list item
 
-        # multiline numbered list item
-        <<-GFM.strip_heredoc,
+          1. Ordered list item 2
+        GFM
+
+        # multiline ordered list item
+        <<~GFM,
           1. Multiline
-              Numbered list item
+
+             Ordered list item
         GFM
 
-        # nested numbered list
-        <<-GFM.strip_heredoc,
+        # nested ordered list
+        <<~GFM,
           1. Nested
 
-              1. Numbered lists
+             1. Ordered lists
         GFM
 
         # list item followed by an HR
-        <<-GFM.strip_heredoc,
-          - list item
+        <<~GFM,
+          * list item
 
-          -----
+          ---
         GFM
 
         '# Heading',
@@ -518,14 +550,14 @@ describe 'Copy as GFM', :js do
 
         '**Bold**',
 
-        '_Italics_',
+        '*Italics*',
 
         '~~Strikethrough~~',
 
-        '-----',
+        '---',
 
         # table
-        <<-GFM.strip_heredoc,
+        <<~GFM,
           | Centered | Right | Left |
           |:--------:|------:|------|
           | Foo | Bar | **Baz** |
@@ -533,9 +565,9 @@ describe 'Copy as GFM', :js do
         GFM
 
         # table with empty heading
-        <<-GFM.strip_heredoc,
+        <<~GFM,
           |  | x | y |
-          |---|---|---|
+          |--|---|---|
           | a | 1 | 0 |
           | b | 0 | 1 |
         GFM
@@ -545,9 +577,11 @@ describe 'Copy as GFM', :js do
     alias_method :gfm_to_html, :markdown
 
     def verify(label, *gfms)
+      markdown_options = gfms.extract_options!
+
       aggregate_failures(label) do
         gfms.each do |gfm|
-          html = gfm_to_html(gfm).gsub(/\A&#x000A;|&#x000A;\z/, '')
+          html = gfm_to_html(gfm, markdown_options).gsub(/\A&#x000A;|&#x000A;\z/, '')
           output_gfm = html_to_gfm(html)
           expect(output_gfm.strip).to eq(gfm.strip)
         end
@@ -594,7 +628,7 @@ describe 'Copy as GFM', :js do
             verify(
               '[id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_10_9"], [id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_10_10"]',
 
-              <<-GFM.strip_heredoc,
+              <<~GFM,
                 ```ruby
                       raise RuntimeError, "System commands must be given as an array of strings"
                     end
@@ -627,7 +661,7 @@ describe 'Copy as GFM', :js do
             verify(
               '[id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_8_8"], [id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_9_9"], [id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_10_9"], [id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_10_10"]',
 
-              <<-GFM.strip_heredoc,
+              <<~GFM,
                 ```ruby
                     unless cmd.is_a?(Array)
                       raise "System commands must be given as an array of strings"
@@ -645,7 +679,7 @@ describe 'Copy as GFM', :js do
             verify(
               '[id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_8_8"], [id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_9_9"], [id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_10_9"], [id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_10_10"]',
 
-              <<-GFM.strip_heredoc,
+              <<~GFM,
                 ```ruby
                     unless cmd.is_a?(Array)
                       raise RuntimeError, "System commands must be given as an array of strings"
@@ -691,7 +725,7 @@ describe 'Copy as GFM', :js do
           verify(
             '.line[id="LC9"], .line[id="LC10"]',
 
-            <<-GFM.strip_heredoc,
+            <<~GFM,
               ```ruby
                     raise RuntimeError, "System commands must be given as an array of strings"
                   end
@@ -733,7 +767,7 @@ describe 'Copy as GFM', :js do
           verify(
             '.line[id="LC27"], .line[id="LC28"]',
 
-            <<-GFM.strip_heredoc,
+            <<~GFM,
               ```json
                   "bio": null,
                   "skype": "",
@@ -752,7 +786,7 @@ describe 'Copy as GFM', :js do
   end
 
   def html_for_selector(selector)
-    js = <<-JS.strip_heredoc
+    js = <<~JS
       (function(selector) {
         var els = document.querySelectorAll(selector);
         var htmls = [].slice.call(els).map(function(el) { return el.outerHTML; });
@@ -763,7 +797,7 @@ describe 'Copy as GFM', :js do
   end
 
   def html_to_gfm(html, transformer = 'transformGFMSelection', target: nil)
-    js = <<-JS.strip_heredoc
+    js = <<~JS
       (function(html) {
         var transformer = window.CopyAsGFM[#{transformer.inspect}];
 
diff --git a/spec/javascripts/behaviors/copy_as_gfm_spec.js b/spec/javascripts/behaviors/copy_as_gfm_spec.js
index cf8c1b77861..6179a02ce16 100644
--- a/spec/javascripts/behaviors/copy_as_gfm_spec.js
+++ b/spec/javascripts/behaviors/copy_as_gfm_spec.js
@@ -87,7 +87,7 @@ describe('CopyAsGFM', () => {
         spyOn(window, 'getSelection').and.returnValue(selection);
         simulateCopy();
 
-        const expectedGFM = '- List Item1\n- List Item2';
+        const expectedGFM = '* List Item1\n\n* List Item2';
 
         expect(clipboardData.setData).toHaveBeenCalledWith('text/x-gfm', expectedGFM);
       });
@@ -97,7 +97,7 @@ describe('CopyAsGFM', () => {
         spyOn(window, 'getSelection').and.returnValue(selection);
         simulateCopy();
 
-        const expectedGFM = '1. List Item1\n1. List Item2';
+        const expectedGFM = '1. List Item1\n\n1. List Item2';
 
         expect(clipboardData.setData).toHaveBeenCalledWith('text/x-gfm', expectedGFM);
       });
diff --git a/spec/javascripts/behaviors/shortcuts/shortcuts_issuable_spec.js b/spec/javascripts/behaviors/shortcuts/shortcuts_issuable_spec.js
index b709b937180..fe827bb1e18 100644
--- a/spec/javascripts/behaviors/shortcuts/shortcuts_issuable_spec.js
+++ b/spec/javascripts/behaviors/shortcuts/shortcuts_issuable_spec.js
@@ -186,7 +186,7 @@ describe('ShortcutsIssuable', function() {
       it('adds the quoted selection to the input', () => {
         ShortcutsIssuable.replyWithSelectedText(true);
 
-        expect($(FORM_SELECTOR).val()).toBe('> _Selected text._\n\n');
+        expect($(FORM_SELECTOR).val()).toBe('> *Selected text.*\n\n');
       });
 
       it('triggers `focus`', () => {
diff --git a/yarn.lock b/yarn.lock
index 8496aac6b2b..dd027355865 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4102,6 +4102,13 @@ fastparse@^1.1.1:
   resolved "https://registry.yarnpkg.com/fastparse/-/fastparse-1.1.1.tgz#d1e2643b38a94d7583b479060e6c4affc94071f8"
   integrity sha1-0eJkOzipTXWDtHkGDmxK/8lAcfg=
 
+fault@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/fault/-/fault-1.0.2.tgz#c3d0fec202f172a3a4d414042ad2bb5e2a3ffbaa"
+  integrity sha512-o2eo/X2syzzERAtN5LcGbiVQ0WwZSlN3qLtadwAz3X8Bu+XWD16dja/KMsjZLiQr+BLGPDnHGkc4yUJf1Xpkpw==
+  dependencies:
+    format "^0.2.2"
+
 faye-websocket@^0.10.0:
   version "0.10.0"
   resolved "https://registry.yarnpkg.com/faye-websocket/-/faye-websocket-0.10.0.tgz#4e492f8d04dfb6f89003507f6edbf2d501e7c6f4"
@@ -4321,6 +4328,11 @@ form-data@~2.3.2:
     combined-stream "^1.0.6"
     mime-types "^2.1.12"
 
+format@^0.2.2:
+  version "0.2.2"
+  resolved "https://registry.yarnpkg.com/format/-/format-0.2.2.tgz#d6170107e9efdc4ed30c9dc39016df942b5cb58b"
+  integrity sha1-1hcBB+nv3E7TDJ3DkBbflCtctYs=
+
 formdata-polyfill@^3.0.11:
   version "3.0.11"
   resolved "https://registry.yarnpkg.com/formdata-polyfill/-/formdata-polyfill-3.0.11.tgz#c82b4b4bea3356c0a6752219e54ce1edb2a7fb5b"
@@ -4819,7 +4831,7 @@ he@^1.1.0, he@^1.1.1:
   resolved "https://registry.yarnpkg.com/he/-/he-1.1.1.tgz#93410fd21b009735151f8868c2f271f3427e23fd"
   integrity sha1-k0EP0hsAlzUVH4howvJx80J+I/0=
 
-highlight.js@^9.13.1:
+highlight.js@^9.13.1, highlight.js@~9.13.0:
   version "9.13.1"
   resolved "https://registry.yarnpkg.com/highlight.js/-/highlight.js-9.13.1.tgz#054586d53a6863311168488a0f58d6c505ce641e"
   integrity sha512-Sc28JNQNDzaH6PORtRLMvif9RSn1mYuOoX3omVjnb0+HbpPygU2ALBI0R/wsiqCb4/fcp07Gdo8g+fhtFrQl6A==
@@ -6470,6 +6482,13 @@ lightercollective@^0.1.0:
   resolved "https://registry.yarnpkg.com/lightercollective/-/lightercollective-0.1.0.tgz#70df102c530dcb8d0ccabfe6175a8d00d5f61300"
   integrity sha512-J9tg5uraYoQKaWbmrzDDexbG6hHnMcWS1qLYgJSWE+mpA3U5OCSeMUhb+K55otgZJ34oFdR0ECvdIb3xuO5JOQ==
 
+linkify-it@^2.0.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/linkify-it/-/linkify-it-2.1.0.tgz#c4caf38a6cd7ac2212ef3c7d2bde30a91561f9db"
+  integrity sha512-4REs8/062kV2DSHxNfq5183zrqXMl7WP0WzABH9IeJI+NLm429FgE1PDecltYfnOoFDFlZGh2T8PfZn0r+GTRg==
+  dependencies:
+    uc.micro "^1.0.1"
+
 load-json-file@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/load-json-file/-/load-json-file-1.1.0.tgz#956905708d58b4bab4c2261b04f59f31c99374c0"
@@ -6631,6 +6650,14 @@ lowercase-keys@1.0.0, lowercase-keys@^1.0.0:
   resolved "https://registry.yarnpkg.com/lowercase-keys/-/lowercase-keys-1.0.0.tgz#4e3366b39e7f5457e35f1324bdf6f88d0bfc7306"
   integrity sha1-TjNms55/VFfjXxMkvfb4jQv8cwY=
 
+lowlight@^1.11.0:
+  version "1.11.0"
+  resolved "https://registry.yarnpkg.com/lowlight/-/lowlight-1.11.0.tgz#1304d83005126d4e8b1dc0f07981e9b689ec2efc"
+  integrity sha512-xrGGN6XLL7MbTMdPD6NfWPwY43SNkjf/d0mecSx/CW36fUZTjRHEq0/Cdug3TWKtRXLWi7iMl1eP0olYxj/a4A==
+  dependencies:
+    fault "^1.0.2"
+    highlight.js "~9.13.0"
+
 lru-cache@2.2.x:
   version "2.2.4"
   resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-2.2.4.tgz#6c658619becf14031d0d0b594b16042ce4dc063d"
@@ -6689,6 +6716,17 @@ map-visit@^1.0.0:
   dependencies:
     object-visit "^1.0.0"
 
+markdown-it@^8.4.2:
+  version "8.4.2"
+  resolved "https://registry.yarnpkg.com/markdown-it/-/markdown-it-8.4.2.tgz#386f98998dc15a37722aa7722084f4020bdd9b54"
+  integrity sha512-GcRz3AWTqSUphY3vsUqQSFMbgR38a4Lh3GWlHRh/7MRwz8mcu9n2IO7HOh+bXHrR9kOPDl5RNCaEsrneb+xhHQ==
+  dependencies:
+    argparse "^1.0.7"
+    entities "~1.1.1"
+    linkify-it "^2.0.0"
+    mdurl "^1.0.1"
+    uc.micro "^1.0.5"
+
 marked@^0.3.12, marked@~0.3.6:
   version "0.3.19"
   resolved "https://registry.yarnpkg.com/marked/-/marked-0.3.19.tgz#5d47f709c4c9fc3c216b6d46127280f40b39d790"
@@ -6707,6 +6745,11 @@ md5.js@^1.3.4:
     hash-base "^3.0.0"
     inherits "^2.0.1"
 
+mdurl@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/mdurl/-/mdurl-1.0.1.tgz#fe85b2ec75a59037f2adfec100fd6c601761152e"
+  integrity sha1-/oWy7HWlkDfyrf7BAP1sYBdhFS4=
+
 media-typer@0.3.0:
   version "0.3.0"
   resolved "https://registry.yarnpkg.com/media-typer/-/media-typer-0.3.0.tgz#8710d7af0aa626f8fffa1ce00168545263255748"
@@ -7420,6 +7463,11 @@ optionator@^0.8.1, optionator@^0.8.2:
     type-check "~0.3.2"
     wordwrap "~1.0.0"
 
+orderedmap@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/orderedmap/-/orderedmap-1.0.0.tgz#d90fc2ba1ed085190907d601dec6e6a53f8d41ba"
+  integrity sha1-2Q/Cuh7QhRkJB9YB3sbmpT+NQbo=
+
 original@^1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/original/-/original-1.0.2.tgz#e442a61cffe1c5fd20a65f3261c26663b303f25f"
@@ -7956,6 +8004,122 @@ prompts@^0.1.9:
     kleur "^2.0.1"
     sisteransi "^0.1.1"
 
+prosemirror-commands@^1.0.7:
+  version "1.0.7"
+  resolved "https://registry.yarnpkg.com/prosemirror-commands/-/prosemirror-commands-1.0.7.tgz#e5a2ba821e29ea7065c88277fe2c3d7f6b0b9d37"
+  integrity sha512-IR8yMSdw7XlKuF68tydAak1J9P/lLD5ohsrL7pzoLsJAJAQU7mVPDXtGbQrrm0mesddFjcc1zNo/cJQN3lRYnA==
+  dependencies:
+    prosemirror-model "^1.0.0"
+    prosemirror-state "^1.0.0"
+    prosemirror-transform "^1.0.0"
+
+prosemirror-dropcursor@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/prosemirror-dropcursor/-/prosemirror-dropcursor-1.1.1.tgz#c60ed1ed6c58804a06a75db06a0d993b087b7622"
+  integrity sha512-GeUyMO/tOEf8MXrP7Xb7UIMrfK86OGh0fnyBrHfhav4VjY9cw65mNoqHy87CklE5711AhCP5Qzfp8RL/hVKusg==
+  dependencies:
+    prosemirror-state "^1.0.0"
+    prosemirror-transform "^1.1.0"
+    prosemirror-view "^1.1.0"
+
+prosemirror-gapcursor@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/prosemirror-gapcursor/-/prosemirror-gapcursor-1.0.3.tgz#acc6537fc5a35e9b38966f91a199a382dfc715c4"
+  integrity sha512-X+hJhr42PcHWiSWL+lI5f/UeOhXCxlBFb8M6O8aG1hssmaRrW7sS2/Fjg5jFV+pTdS1REFkmm1occh01FMdDIQ==
+  dependencies:
+    prosemirror-keymap "^1.0.0"
+    prosemirror-model "^1.0.0"
+    prosemirror-state "^1.0.0"
+    prosemirror-view "^1.0.0"
+
+prosemirror-history@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/prosemirror-history/-/prosemirror-history-1.0.3.tgz#5fb8591adfc272afaaf0b41bec64ee7d9522a118"
+  integrity sha512-IfFGbhafSx+R3aq7nLJGkXeu2iaUiP8mkU3aRu2uQcIIjU8Fq7RJfuvhIOJ2RNUoSyqF/ANkdTjnZ74F5eHs1Q==
+  dependencies:
+    prosemirror-state "^1.2.2"
+    prosemirror-transform "^1.0.0"
+    rope-sequence "^1.2.0"
+
+prosemirror-inputrules@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/prosemirror-inputrules/-/prosemirror-inputrules-1.0.1.tgz#f63305fd966379f218e82ca76a2a9b328b66dc7b"
+  integrity sha512-UHy22NmwxS5WIMQYkzraDttQAF8mpP82FfbJsmKFfx6jwkR/SZa+ZhbkLY0zKQ5fBdJN7euj36JG/B5iAlrpxA==
+  dependencies:
+    prosemirror-state "^1.0.0"
+    prosemirror-transform "^1.0.0"
+
+prosemirror-keymap@^1.0.0, prosemirror-keymap@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/prosemirror-keymap/-/prosemirror-keymap-1.0.1.tgz#03ef32b828e3a859dfb570eb84928bf2e5330bc2"
+  integrity sha512-e79ApE7PXXZMFtPz7WbjycjAFd1NPjgY1MkecVz98tqwlBSggXWXYQnWFk6x7UkmnBYRHHbXHkR/RXmu2wyBJg==
+  dependencies:
+    prosemirror-state "^1.0.0"
+    w3c-keyname "^1.1.8"
+
+prosemirror-markdown@^1.3.0:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/prosemirror-markdown/-/prosemirror-markdown-1.3.0.tgz#a100d14c27da7d8fb70818230d786898eeadb7fa"
+  integrity sha512-76l3yLB/suy6sA7LpzRJvRRWkHtKwOTpgWVNwmlIAIIZJeMypWSPldT/gFyIG604eyXEPZitnx+j80Y2DpbnUQ==
+  dependencies:
+    markdown-it "^8.4.2"
+    prosemirror-model "^1.0.0"
+
+prosemirror-model@^1.0.0, prosemirror-model@^1.1.0, prosemirror-model@^1.6.4:
+  version "1.6.4"
+  resolved "https://registry.yarnpkg.com/prosemirror-model/-/prosemirror-model-1.6.4.tgz#2ac37a629448a7dbfd1635450e2fdd63c3450d7d"
+  integrity sha512-C2ALle8fZsAza+6stUF9Gv28jH9XtpNeczb33bowGlnb2cpNI4FZf1HHUyZjf6ou4cEvOlbt6fAYsT4NCKmlcQ==
+  dependencies:
+    orderedmap "^1.0.0"
+
+prosemirror-schema-list@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/prosemirror-schema-list/-/prosemirror-schema-list-1.0.1.tgz#f216e0cf4809b6074aa27912449ac89897f1ae94"
+  integrity sha512-AiLIX6qm6PEeDtMCKZLcSLi55WXo1ls7DnRK+4hSkoi0IIzNdxGsRlecCd3MzEu//DVz3nAEh+zEmslyW+uk8g==
+  dependencies:
+    prosemirror-model "^1.0.0"
+    prosemirror-transform "^1.0.0"
+
+prosemirror-state@^1.0.0, prosemirror-state@^1.2.1, prosemirror-state@^1.2.2:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/prosemirror-state/-/prosemirror-state-1.2.2.tgz#8df26d95fd6fd327c0f9984a760e84d863204154"
+  integrity sha512-j8aC/kf9BJSCQau485I/9pj39XQoce+TqH5xzekT7WWFARTsRYFLJtiXBcCKakv1VSeev+sC3bJP0pLfz7Ft8g==
+  dependencies:
+    prosemirror-model "^1.0.0"
+    prosemirror-transform "^1.0.0"
+
+prosemirror-tables@^0.7.10, prosemirror-tables@^0.7.9:
+  version "0.7.10"
+  resolved "https://registry.yarnpkg.com/prosemirror-tables/-/prosemirror-tables-0.7.10.tgz#4b0f623422b4b8f84cdc9c559f8a87579846b3ba"
+  integrity sha512-VIu7UGS9keYEHs0Y6AEOTGbNE9QI2rL1OKng4vV6yoTshW/lYcb+s3hGXI12i+WLMjDVm7ujhfdWrpKpvFZOkQ==
+  dependencies:
+    prosemirror-keymap "^1.0.0"
+    prosemirror-model "^1.0.0"
+    prosemirror-state "^1.0.0"
+    prosemirror-transform "^1.0.0"
+    prosemirror-view "^1.0.0"
+
+prosemirror-transform@^1.0.0, prosemirror-transform@^1.1.0:
+  version "1.1.3"
+  resolved "https://registry.yarnpkg.com/prosemirror-transform/-/prosemirror-transform-1.1.3.tgz#28cfdf1f9ee514edc40466be7b7db39eed545fdf"
+  integrity sha512-1O6Di5lOL1mp4nuCnQNkHY7l2roIW5y8RH4ZG3hMYmkmDEWzTaFFnxxAAHsE5ipGLBSRcTlP7SsDhYBIdSuLpQ==
+  dependencies:
+    prosemirror-model "^1.0.0"
+
+prosemirror-utils@^0.7.5:
+  version "0.7.5"
+  resolved "https://registry.yarnpkg.com/prosemirror-utils/-/prosemirror-utils-0.7.5.tgz#11b477647b672ec8f10679ab298a5823dad6457a"
+  integrity sha512-F+63BUiBkUQb1S07c3rGHXjE4MDaZ5OjsNhmaO7eDdSh1lUNORTJJHrvlFEZKnLM7ChoDDXTIKhWNQwnCssQfA==
+
+prosemirror-view@^1.0.0, prosemirror-view@^1.1.0, prosemirror-view@^1.6.8:
+  version "1.6.8"
+  resolved "https://registry.yarnpkg.com/prosemirror-view/-/prosemirror-view-1.6.8.tgz#33fc1a6e2731633e5d6dc1af1967378f15810b74"
+  integrity sha512-YWX3rfji77xsU5EErt4ZoecVytYW9/4oHBYhV1MUHGMYIcppe+QZEBgRlyPMBUuu0lxdZX4m3sq7fCsDvv/MlQ==
+  dependencies:
+    prosemirror-model "^1.1.0"
+    prosemirror-state "^1.0.0"
+    prosemirror-transform "^1.1.0"
+
 proto-list@~1.2.1:
   version "1.2.4"
   resolved "https://registry.yarnpkg.com/proto-list/-/proto-list-1.2.4.tgz#212d5bfe1318306a420f6402b8e26ff39647a849"
@@ -8549,6 +8713,11 @@ ripemd160@^2.0.0, ripemd160@^2.0.1:
     hash-base "^2.0.0"
     inherits "^2.0.1"
 
+rope-sequence@^1.2.0:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/rope-sequence/-/rope-sequence-1.2.2.tgz#49c4e5c2f54a48e990b050926771e2871bcb31ce"
+  integrity sha1-ScTlwvVKSOmQsFCSZ3HihxvLMc4=
+
 rsvp@^3.3.3:
   version "3.6.2"
   resolved "https://registry.yarnpkg.com/rsvp/-/rsvp-3.6.2.tgz#2e96491599a96cde1b515d5674a8f7a91452926a"
@@ -9497,6 +9666,57 @@ tiny-emitter@^2.0.0:
   resolved "https://registry.yarnpkg.com/tiny-emitter/-/tiny-emitter-2.0.2.tgz#82d27468aca5ade8e5fd1e6d22b57dd43ebdfb7c"
   integrity sha512-2NM0auVBGft5tee/OxP4PI3d8WItkDM+fPnaRAVo6xTDI2knbz9eC5ArWGqtGlYqiH3RU5yMpdyTTO7MguC4ow==
 
+tiptap-commands@^1.4.0:
+  version "1.4.0"
+  resolved "https://registry.yarnpkg.com/tiptap-commands/-/tiptap-commands-1.4.0.tgz#0cfb3ac138ee3099de56114cb119abd841fbcbe7"
+  integrity sha512-ytO8jFXgufK5DziamTaVojzUTolWvL4m2xNXaLkAVJYy9CWXruMK7avqeLoFYPI4GZlhleMn5i4gzYTbD7e2jA==
+  dependencies:
+    prosemirror-commands "^1.0.7"
+    prosemirror-inputrules "^1.0.1"
+    prosemirror-schema-list "^1.0.1"
+    prosemirror-state "^1.2.2"
+    tiptap-utils "^1.1.1"
+
+tiptap-extensions@^1.8.0:
+  version "1.8.0"
+  resolved "https://registry.yarnpkg.com/tiptap-extensions/-/tiptap-extensions-1.8.0.tgz#3067620a024f1a9e5fae4450790b143d7ebe4394"
+  integrity sha512-1JN9uk5QnA7DTID1j07gIBEqeOnRd6lwZ5rx/zqWXJLyreZu8VDPvP939tfP41GskO4oicGlhmsQ0aEnA5QYDw==
+  dependencies:
+    lowlight "^1.11.0"
+    prosemirror-history "^1.0.3"
+    prosemirror-state "^1.2.2"
+    prosemirror-tables "^0.7.10"
+    prosemirror-utils "^0.7.5"
+    prosemirror-view "^1.6.8"
+    tiptap "^1.8.0"
+    tiptap-commands "^1.4.0"
+
+tiptap-utils@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/tiptap-utils/-/tiptap-utils-1.1.1.tgz#e7aad3e84eb35f7abed704d15da0420029789d0d"
+  integrity sha512-yPIWwLFaL5a0GC7fcO7aoPlASnH3wOUQex0IlepNWbDCNycSL8shXhVx0HMN/tCnlp943zw1bwcYzpTW3wA4tw==
+  dependencies:
+    prosemirror-model "^1.6.4"
+    prosemirror-state "^1.2.2"
+    prosemirror-tables "^0.7.9"
+    prosemirror-utils "^0.7.5"
+
+tiptap@^1.8.0:
+  version "1.8.0"
+  resolved "https://registry.yarnpkg.com/tiptap/-/tiptap-1.8.0.tgz#c671188075ffa5ee4f86470f95818fd9ce6f1040"
+  integrity sha512-zIcVY8U1Wgj4bg3R4pX5a2BCpZUw/dTCh259VZ9g5MtClnzdLW2XpKCcwqfa9iUBEs6MCPSnB3t8jGRtGciHJg==
+  dependencies:
+    prosemirror-commands "^1.0.7"
+    prosemirror-dropcursor "^1.1.1"
+    prosemirror-gapcursor "^1.0.3"
+    prosemirror-inputrules "^1.0.1"
+    prosemirror-keymap "^1.0.1"
+    prosemirror-model "^1.6.4"
+    prosemirror-state "^1.2.1"
+    prosemirror-view "^1.6.8"
+    tiptap-commands "^1.4.0"
+    tiptap-utils "^1.1.1"
+
 tmp@0.0.33, tmp@0.0.x, tmp@^0.0.33:
   version "0.0.33"
   resolved "https://registry.yarnpkg.com/tmp/-/tmp-0.0.33.tgz#6d34335889768d21b2bcda0aa277ced3b1bfadf9"
@@ -9648,6 +9868,11 @@ typescript@^2:
   resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.9.2.tgz#1cbf61d05d6b96269244eb6a3bce4bd914e0f00c"
   integrity sha512-Gr4p6nFNaoufRIY4NMdpQRNmgxVIGMs4Fcu/ujdYk3nAZqk7supzBE9idmvfZIlH/Cuj//dvi+019qEue9lV0w==
 
+uc.micro@^1.0.1, uc.micro@^1.0.5:
+  version "1.0.5"
+  resolved "https://registry.yarnpkg.com/uc.micro/-/uc.micro-1.0.5.tgz#0c65f15f815aa08b560a61ce8b4db7ffc3f45376"
+  integrity sha512-JoLI4g5zv5qNyT09f4YAvEZIIV1oOjqnewYg5D38dkQljIzpPT296dbIGvKro3digYI1bkb7W6EP1y4uDlmzLg==
+
 uglify-js@^3.1.4:
   version "3.4.9"
   resolved "https://registry.yarnpkg.com/uglify-js/-/uglify-js-3.4.9.tgz#af02f180c1207d76432e473ed24a28f4a782bae3"
@@ -10052,6 +10277,11 @@ w3c-hr-time@^1.0.1:
   dependencies:
     browser-process-hrtime "^0.1.2"
 
+w3c-keyname@^1.1.8:
+  version "1.1.8"
+  resolved "https://registry.yarnpkg.com/w3c-keyname/-/w3c-keyname-1.1.8.tgz#4e2219663760fd6535b7a1550f1552d71fc9372c"
+  integrity sha512-2HAdug8GTiu3b4NYhssdtY8PXRue3ICnh1IlxvZYl+hiINRq0GfNWei3XOPDg8L0PsxbmYjWVLuLj6BMRR/9vA==
+
 walker@~1.0.5:
   version "1.0.7"
   resolved "https://registry.yarnpkg.com/walker/-/walker-1.0.7.tgz#2f7f9b8fd10d677262b18a884e28d19618e028fb"