EM-Dash MD
A cloud-first Markdown editor that lives in your browser. Sign in once and your documents follow you everywhere — stored securely in Firestore, never on your device.
Launch App →
Features
- Secure sign-in — Google account or email/password
- Cloud storage — Documents stored in Firestore, scoped to your account
- Split view — Markdown editor on the left, live rendered preview on the right
- Auto-save — Changes save automatically 2 seconds after you stop typing
- Focus mode — Distraction-free full-screen WYSIWYG writing (F11)
- Find & Replace — With match navigation and replace-all
- Export — Download as MD, TXT, HTML, PDF, DOCX, or RTF
- Import — Upload local
.md or .txt files directly into your cloud library
- Syntax highlighting — Fenced code blocks with language detection
- Themes — Lokai (dark editor / white chrome), Dark, Light
- Installable — Works as a PWA on desktop, iPhone, and iPad
- Preview zoom — Scale the preview pane independently of the editor
- Document tags — Tag documents and filter your library by tag; tags are stored in Firestore alongside the document
- Sidebar navigation — persistent left panel showing your document list with search, new-document button, and browse-all link; collapsible via toolbar button or Ctrl/Cmd+\
- Nested pages — documents can be organized into a hierarchy; create child pages from the sidebar context menu and drag to rearrange
- Trash bin — deleted documents move to Trash and can be restored or permanently deleted; accessible via the sidebar footer
- Full-text search — the document browser searches inside document content and shows a highlighted snippet when the match is in the body rather than the title or tags
- Table insert — toolbar button inserts a Markdown table; the dropdown arrow opens a 5×5 grid picker to choose the exact dimensions
- Mermaid diagrams — fenced code blocks tagged
```mermaid render as live diagrams in the preview pane
- Folders: create folders in the sidebar and put documents or other folders inside; a new folder opens in rename mode, and folders sort first
- Right-click menu: right-click (or long-press on touch) a sidebar item for Rename, Move to, Duplicate, New sub-page or folder, and Move to Trash; right-click empty space for New document or New folder
- Command palette: Ctrl/Cmd+K opens a fuzzy finder for commands and documents; start with
> to search commands only
- Delete My Account — permanently delete your account and all documents from within the app, after typed confirmation and re-authentication
Keyboard Shortcuts
| Action | Shortcut |
|---|
| Save | Ctrl/Cmd+S |
| New document | Ctrl/Cmd+N |
| Open document | Ctrl/Cmd+O |
| Find & Replace | Ctrl/Cmd+F |
| Focus Mode | F11 or Ctrl/Cmd+Shift+F |
| Bold | Ctrl/Cmd+B |
| Italic | Ctrl/Cmd+I |
| Zoom in / out | Ctrl/Cmd+= / Ctrl/Cmd+- |
| Reset zoom | Ctrl/Cmd+0 |
| Toggle sidebar | Ctrl/Cmd+\ |
| Command palette | Ctrl/Cmd+K |
Self-Hosting
To run your own instance against your own Firebase project:
1. Create a Firebase project
- Go to console.firebase.google.com and create a project
- Authentication → Sign-in method → enable Email/Password and Google
- Firestore Database → Create database → production mode
- Firestore → Indexes → add a composite index:
- Collection:
documents
- Fields:
userId Ascending, updatedAt Descending
- Firestore → Rules → paste the contents of
firestore.rules
- Project Settings → Your apps → register a Web app → copy the config object
2. Add your config
Copy firebase-config.example.js to firebase-config.js and fill in your values:
const FIREBASE_CONFIG = {
apiKey: "AIza...",
authDomain: "your-project.firebaseapp.com",
projectId: "your-project",
storageBucket: "your-project.appspot.com",
messagingSenderId: "000000000000",
appId: "1:000000000000:web:abc123"
};
firebase-config.js is gitignored and never committed.
3. Deploy
npm install -g firebase-tools
firebase login
firebase deploy
The repo already contains firebase.json and .firebaserc, so do not run firebase init hosting (it can overwrite them). Edit .firebaserc to point at your own project instead.
Hosting serves the project root ("public": "."), so everything not listed in the ignore array of firebase.json is public. The list already excludes tests, scripts, patches, package*.json, buildme.sh, Firestore files and key files. If you add a new file or folder that must stay private, add it to that list. npm run test:unit fails if the key entries are removed. After a deploy, the file count it prints should match what you expect to serve (25 at v3.29.1).
Testing
npm install
npx playwright install chromium # once, for the browser tests
npm test # syntax check, unit, round-trip and browser tests
The browser tests (tests/e2e-*.cjs) run the real app in headless Chromium against an in-memory Firebase stub, so they never touch your Firestore data. npm run test:unit runs only the fast tests.
Security
- Documents are scoped to each user's UID — Firestore rules block cross-user access server-side
- Content Security Policy restricts all resource origins
- Markdown preview is sanitized with DOMPurify before rendering
firebase-config.js is gitignored and never touches the repository
Tech Stack
Plain HTML, CSS, and JavaScript — no build step, no framework.
| Library | Purpose |
|---|
| Firebase Auth (compat v9) | Authentication |
| Cloud Firestore (compat v9) | Document storage |
| Marked | Markdown → HTML |
| highlight.js | Syntax highlighting |
| DOMPurify | XSS sanitization |
| Turndown | HTML → Markdown (focus mode exit) |
| Mermaid | Diagram rendering |
| Firebase Hosting | Deployment |
Changelog
v3.30.0
- New: the search boxes in the sidebar and in Open Document have an ✕ button that clears the text and restores the full list
v3.29.1
- Security: risky HTML in diagram labels is removed before the diagram library sees it (the browser security policy was already blocking it)
- Security: hosting no longer serves
tests/, buildme.sh or _to_delete/; a test guards the ignore list
- Cleanup: the retired MCP server, its Dockerfile and the
firebase-admin dependency were removed from the repository
v3.29.0
- Fix: storage access can no longer stop the app from starting (blocked or corrupt browser storage is ignored)
- Fix: saves are queued one at a time, a save no longer marks text typed during it as saved, and saving over a version changed on another device asks first
- Security: diagrams are rendered in strict mode, sanitized and cached
- Security: signing out or deleting the account clears the offline cache and every list on screen, then reloads
- Fix: HTML, PDF and Word exports no longer contain copy buttons, and RTF export keeps tables
- Fix: list continuation, Replace All and leaving Focus Mode keep Ctrl+Z history
- Fix: email and password sign-up sends a verification email and explains the next step
- Offline: Firebase and diagram libraries are cached, and app files are always revalidated
v3.28.0
- Fix (cost): saving no longer re-reads 300 documents; the sidebar is updated from memory. Trash and Kanban read only the documents they show
- Fix: trashed documents no longer use up slots in the 300-document sidebar window, and a page whose parent is outside the window keeps its place in the tree
- Fix: edits made in Focus Mode and with Replace All are now auto-saved
- Fix: signing out and back in no longer doubles sidebar and mobile handlers
v3.27.0
- Folders: real folders in the sidebar (stored as documents with
type: folder, so no migration or rules change). Move to Trash takes the folder and everything inside it; Restore and Delete permanently from Trash act on the whole folder
- Right-click context menu: sidebar items and empty sidebar space, with keyboard navigation and touch long-press
- Command palette: Ctrl/Cmd+K, fuzzy search across commands and documents
- Fix: a new document no longer inherits the previously open document's parent page
v3.26.0
- Sidebar sort toggle — switch between Groups (hierarchical tree) and Name (flat A–Z list) using the toggle below the search box; preference persists across sessions
v3.25.0
- Resizable sidebar — drag the handle between the sidebar and editor to set any width you like; the chosen width persists across sessions; double-click the handle to reset to the default
v3.24.0
- Mermaid diagrams — fenced code blocks tagged
```mermaid render as live flowcharts, sequence diagrams, Gantt charts, and more in the preview pane
- Table insert — new toolbar split-button inserts a default Markdown table; the dropdown arrow opens a 5×5 hover grid to pick exact dimensions
- Full-text search — document browser now searches inside document content; matching body text shows a highlighted snippet beneath the title
- Trash bin — deleted documents are soft-deleted and moved to Trash (sidebar footer icon); restore individual documents or empty the trash permanently
v3.23.0
- Nested pages — documents can be organized into a parent/child hierarchy from the sidebar; drag to rearrange, and expand/collapse subtrees
v3.22.0
- Sidebar navigation — persistent left panel (Notion/Anytype-style) shows your recent documents, a search field, a new-document button, and a "Browse all" link to the full document browser; collapses inline on desktop or slides in as an overlay on mobile; state persists across sessions
v3.19.2
- Resizable document browser — drag the grip in the bottom-right corner of the Open Document window to resize it; the chosen size is remembered across sessions
v3.19.0
- Domain restriction — access is now limited to
@michaelson-clark.com accounts; unauthorized users are signed out immediately with a clear message, and Firestore rules enforce the same check at the database level (requires email verification)
v3.18.0
- Delete My Account — new danger-zone option in the ellipsis menu; requires typing "DELETE" and re-authenticating (password re-entry, or a Google re-auth popup) before permanently deleting all documents and the account itself
v3.17.0
- Local caching — Firestore reads are now cached in IndexedDB (
enablePersistence); the Open Document browser paints instantly from the local cache and refreshes from the server in the background (stale-while-revalidate) instead of waiting on a round trip every time it opens
- Document browser redesigned — replaced the card layout with a compact, Finder-style list: click the Name / Words / Date Modified column headers to sort (ascending/descending), tags now sit inline next to the title and their edit control appears on hover
- Browser modal widened to 760px for the new column layout; the old Newest/Oldest/A-Z/Z-A sort dropdown and the 2-line content preview were removed in favor of the sortable columns
- Service worker cache bumped to
em-dash-md-v3 so installed/PWA users pick up this update instead of serving a stale cached copy
v3.16.0
- Enriched document browser — each entry now shows a file-type badge (MD, TXT, etc.), word count, date created, date modified, and a 2-line content preview with markdown syntax stripped
- Tags — add comma-separated tags to any document directly in the browser; tags are stored in Firestore and persist across sessions
- Tag filter — filter the document list by tag using the new dropdown next to the search box; search also matches tag text
- Browser modal widened to 640 px to accommodate the richer layout
v3.15.5
- Word goal: click the word count in the status bar to set a target; turns accent color when met; persists across sessions
v3.15.4
- Document browser now shows a count in the footer ("N documents", or "N of M" when searching)
v3.15.3
- Document browser sort: Newest, Oldest, A-Z, Z-A controls added next to the search box
v3.15.2
- Rename and Duplicate added to the ellipsis menu
v3.15.1
- Trash/undo: deleting a document now shows a 5-second undo toast instead of a confirmation dialog
v3.15.0
License
MIT
