Blockdown for VS Code

Block-based markdown editor inside VS Code. Opens .md files in a Jupyter-style rendered view where each heading, paragraph, list, code block, table, and mermaid diagram is a selectable, navigable block. Drop into an in-place CodeMirror editor for a single block, render back, keep moving.

Backed by the standalone blockdown editor — same rendering, same keybindings, same feel — but with real VS Code file integration: dirty state, save, external edits, workspace-relative settings.

Install

Not yet on the marketplace. Install from a locally built .vsix:

git clone https://github.com/FloG309/blockdown.git
cd blockdown/extension
npm install
npm run package        # produces blockdown-vscode-<version>.vsix
code --install-extension blockdown-vscode-*.vsix

Use

Open a .md file in Blockdown — Right-click a .md file in the Explorer → "Open with Blockdown". Or run the Blockdown: Open with Blockdown command on the active editor.
.md still opens in the default editor by default — the extension is registered with priority: "option", so you have to pick it explicitly. To make it the default, use the workbench.editorAssociations setting:
```
"workbench.editorAssociations": {
  "*.md": "blockdown.editor"
}
```

Editing model (same as standalone)

Key	Action
Arrow Up/Down	Navigate blocks
Shift+Arrow Up/Down	Multi-select
Enter	Edit selected block(s)
Escape	Deselect / exit edit
Shift+Enter	Render and exit edit
`a` / `b`	Insert block above / below
`c` / `v` / `x`	Copy / paste / cut blocks (internal clipboard)
`d d`	Delete selected blocks
Ctrl+A	Select all
Ctrl+Z / Ctrl+Y	Undo / redo

All shortcuts are remappable from the gear-icon settings panel → Shortcuts.

What syncs where

Document text — authoritative in VS Code's TextDocument. Blockdown reflects it; edits in Blockdown apply as WorkspaceEdits so save / dirty / hot-exit all work. External edits to the same file update the webview.
Layout settings (theme, font size, line height, spacing, content width) — per workspace via Memento.workspaceState.
Keybindings — global via Memento.globalState, so a custom binding follows you across projects.

Known gaps

Markdown → HTML → markdown round trip is not identity-preserving; opening some files may produce a dirty state on first edit due to minor whitespace normalization by Turndown.
Very large files (500+ KB): every keystroke schedules a serialize + apply. Fine for typical docs; unrefined for book-sized manuscripts.
One CodeMirror instance per block in edit mode. Opening 100+ blocks into edit mode simultaneously will be slow.

License

ISC (see LICENSE).

Blockdown

greibo