Impower

Monorepo for Sparkdown — a markup language for writing screenplays and games — and the tools around it: the impower.dev web editor, the VS Code extension, the language server, the game engine, and the player.

Recommended Workspace Setup

1. Install IDE: Visual Studio Code
2. In VSCode, install all Workspace Recommended Extensions.

Local development

This is an npm-workspaces monorepo. Install once from the repo root, then use the root launch scripts below — they are the supported way to run things and they keep the multi-process wiring correct.

npm install        # once, at the repo root — sets up every workspace

To work on…	Run (from the repo root)	What it does
The web editor (impower-dev)	npm run web:dev	Launches the editor and the game-preview player together, on auto-picked free ports, and prints the editor URL. Ctrl+C stops both.
…forcing a separate-origin player iframe	npm run web:dev:cross-origin	Same, but cross-origin instead of the default same-origin proxy. (web:dev:same-origin is the explicit default.)
The VS Code extension (vscode-sparkdown)	npm run vscode:dev	Builds + watches the extension and everything it bundles; press F5 in VS Code to open an Extension Development Host.

Override the web ports with the EDITOR_PORT / PLAYER_PORT / HMR_PORT env vars if you need fixed ports.

Why web:dev instead of launching the two servers yourself

The editor embeds the game player as an <iframe> and the two connect over a postMessage/MessageChannel handshake. That handshake needs three things to agree: the editor's player-origin, the player's editor-origin, and a unique HMR port per editor. Get any of them wrong — or collide with another running checkout — and the Game Preview silently stays black even on PLAY (the editor never finishes connecting; the editor pane itself looks fine). The values are baked into each Vite bundle at startup, so a page reload won't fix a wrong one. web:dev removes the footgun entirely: it derives every value consistently and never collides (every port is chosen free at launch). Just run it and open the URL it prints.

Same-origin mode (the default) additionally exposes window.__preview in the editor page so you can inspect the live game DOM from the console / devtools.