Create-SJMCL-Extension CLI

create-sjmcl-extension scaffolds an SJMCL extension project with a local build pipeline for src/ tree and npm dependencies.

Install

npm install -g create-sjmcl-extension@latest

Usage

npx create-sjmcl-extension

CLI Options

Base command: create-sjmcl-extension

Command	Value	Default	Description
[project-directory]	path	my-sjmcl-extension	Scaffold a new extension project.
sync-types [project-directory]	path	current directory	Regenerate only src/types/host.ts in an existing project from the latest scaffold template.
--help	none	off	Show the CLI help screen.

It will interactively prompt for the new extenion's metadata.

npx create-sjmcl-extension
npx create-sjmcl-extension my-extension
npx create-sjmcl-extension sync-types .
npx create-sjmcl-extension sync-types ./existing-extension

Generated Project

The generated project includes a small build pipeline and three project scripts:

npm run dev

Starts a development server that watches source files, rebuilds on change, and writes output directly to SJMCL's installed extension directory. A sjmcl://reload-extension?id=<identifier> deeplink is fired after each build so the launcher reloads the extension automatically.

The extension must be manually enabled in Settings → Extensions first. Use the refresh button if it doesn't appear.

npm run dev
npm run dev -- --mode production
npm run dev -- --compress
npm run dev -- --no-reload
npm run dev -- --path ./custom-output

npm run build

Builds the extension package from the local source tree.

Build characteristics:

• Source entry: src/index.ts or src/index.tsx
• JSX transform: React.createElement(...)
• Default output: minified production bundle

Build options:

Flag	Value	Default	Effect
--mode	production, development	production	Selects the overall build profile and sets process.env.NODE_ENV. production enables syntax and whitespace minification for a compact release bundle; development keeps the output more readable for inspection and debugging.
--obfuscate	none or boolean (true, false, 1, 0, yes, no, on, off)	on in production, off in development	Controls identifier minification only. It renames local symbols to shorter names, but it does not switch build mode or enable syntax/whitespace minification by itself.

In short: --mode chooses the overall output style, while --obfuscate only toggles identifier mangling.

npm run build
npm run build -- --mode development
npm run build -- --obfuscate
npm run build -- --obfuscate=off
npm run build -- --mode development --obfuscate=off

Build output files:

• dist/<identifier>/
• dist/<identifier>-<version>.sjmclx

The build script also copies these files into the packaged output when present:

• sjmcl.ext.json
• icon.png
• assets/
• data/

npm run bump -- <semver>

Updates both package.json and sjmcl.ext.json to the exact version you provide.

Host-Provided Singleton Packages

Direct imports from these packages are rejected at build time:

Package	Use Instead
react	api.React
@chakra-ui/react	api.ChakraUI

If a third-party dependency bundles them transitively, the build still succeeds and emits warnings that include:

• the bundled singleton package name
• the byte contribution in the final output
• one or more dependency chains from project source to the bundled package

References

• SJMCL extension system overview
• SJMCL extension file structure
• SJMCL extension quick start