Markdown and Vim editing

Open a text note or choose Take a note…. Checklists keep their separate checklist editor.

• Write, Preview and Split change the view without discarding source or enhanced-editor undo. Split stacks vertically on narrow screens.
• Standard keys work by default. Vim enables normal/insert/visual modes, motions, selection and Vim undo. Use i to insert, Escape to return to normal, v to select and u to undo. Escape in Vim stays inside the note.
• Simple text provides a native textarea for accessibility, device compatibility or enhanced-editor loading failure. Switching to/from it starts fresh enhanced-editor undo; source is retained. Settings apply to this editing session.
• Undo, Redo, Find and the formatting buttons work in the enhanced editor. Find includes replacement. Tab leaves the editor instead of trapping keyboard focus.
• Save or Ctrl/Cmd-S writes through the normal API. Vim :w uses the same path. Existing notes stay open after these saves; Save & close also closes. Saving a new note completes its creation. Escape/backdrop closure asks before discarding an edited note; it does not silently save it.
• A failed save leaves the draft and undo available. If another tab changed the note, copy or download the draft before Reload saved version. Reloading is a deliberate replacement and clears the old draft’s undo history. There is no durable server revision archive yet.
• Download .md exports the exact current body, including unsaved changes, with the title as a portable filename. It does not insert a heading or modify stored data. Account JSON export still includes all notes and labels.

Privacy and limits

Markdown rendering, syntax and Vim run in the browser. No AI request, external font or paid processing provider is added. Preview supports CommonMark and GFM tables/task lists. Raw HTML is ignored. Only explicit HTTP(S), mail and fragment links are clickable; application-relative and script/data/file links are disabled. External links open separately without a referrer. Images display their description and an optional external link, never an automatic image request.

Source text remains in the existing note body; no database migration is needed. The enhanced editor preserves whitespace and mixed line separators by using explicit LF splitting. Its 100,000 UTF-16-unit limit matches the existing API boundary. An oversized paste is rejected whole, with a visible message, rather than silently truncated. Account-wide quotas and request limits still apply.

Drafts and undo exist only in the open tab. Save before navigating, and keep downloads/backups for important material. A tab-close warning is not crash recovery. Neither content nor editor preferences are copied into localStorage. This is not end-to-end encryption.

Public example

/example uses the same editor with original demonstration text. It needs no account and sends no scratchpad to an API. Its Ctrl/Cmd-S and Vim :w download Markdown. Reset and ordinary navigation warn before discarding changed content. This is a scratchpad demonstration, not simulated cloud persistence.

Implementation

MarkdownEditor owns views, fallback, status and download; CodeEditor owns one CodeMirror instance with replaceable key/read-only compartments. Callbacks route through the current component state; the global Vim Ex command routes through a WeakMap keyed by actual editor instance. Component cleanup destroys the view and removes its save handler. Switching views/keys retains history; a deliberate saved-version reload remounts it.

Both enhanced editing and Markdown preview load in separate client chunks. A failed editor chunk falls back to the controlled native textarea, preserving text. A failed preview chunk leaves Write available. The dependency set is pinned in the lockfile; CodeMirror, its Vim adapter, react-markdown and remark-gfm are MIT licensed. No raw-HTML plugin or weakened script CSP is used.

Primary references: CodeMirror state/view documentation , official Vim adapter , react-markdown security , remark-gfm . Installed Next 16.3.8 client/lazy-loading guides were read for this implementation.

Automated browser evidence is Chromium on Linux. Physical mobile keyboards, IME composition, screen readers and Safari/Firefox remain separate compatibility checks; the native textarea is available without pretending those devices have been certified.