Extension Assembly Pipeline

LightningAddon uses a two-stage build: each app is built by Vite, then repo-assemble combines them into a single extension package.

Stage 1: Vite Builds

Each extension context builds independently:

App	Output	Purpose
apps/background	dist/background.js	Service worker
apps/popup	dist/popup.html, dist/assets/*	Extension popup
apps/main	dist/index.html, dist/assets/*	Full-page dashboard
apps/in-page	dist/content_script.js	Content script injected into pages

Builds run in parallel via Turborepo. Each app has its own dist/ directory.

Stage 2: Assembly

The repo-assemble CLI (from @repo/tooling) reads apps/extension/extension.config.mjs and:

1. Clears apps/extension/dist/
2. Copies artifacts from each app's dist/ into the output directory
3. Copies assets from packages/assets
4. Injects the correct manifest (manifest.chrome.json or manifest.firefox.json) as manifest.json

Configuration

extension.config.mjs defines:

• manifests — Which manifest file to use per build env (chrome, firefox)
• artifacts — Which files to copy and where (e.g. popup.html, background.js, content_script.js)
• assetsDir — Icons and static files
• assetExcludes — Files to skip when copying assets

Build Commands

pnpm build:chrome   # BUILD_ENV=chrome → uses manifest.chrome.json
pnpm build:firefox  # BUILD_ENV=firefox → uses manifest.firefox.json

Both produce output in apps/extension/dist/. Load that directory as an unpacked extension in Chrome or Firefox.

Adding a Store-Specific Build

To target a specific store (e.g. Edge with its own listing):

1. Add manifest.edge.json to apps/extension/manifests/
2. Register it in extension.config.mjs:

   manifests: {
     chrome: 'manifest.chrome.json',
     firefox: 'manifest.firefox.json',
     edge: 'manifest.edge.json',
   },

3. Run BUILD_ENV=edge pnpm build (or add build:edge script)

No source code changes needed—only the manifest differs.

Artifact Dependencies

The assemble step requires that dependent packages have already built. Turborepo's ^build graph ensures @repo/background, @repo/popup, etc. are built before assemble runs.