build subpackages with a script

.gitignore

@@ -8,4 +8,11 @@ download-binaries/*
 
 bin/*
 
+# copied from the root directory
+/packages/*/LICENSE
+/packages/*/index.js
+/packages/*/install.js
+# generated by build scripts
+/packages/*/package.json
+# not relevant
 /packages/*/package-lock.json

build-packages.js

@@ -0,0 +1,70 @@
+#!/usr/bin/env node
+
+const {join: pathJoin} = require('path')
+const {cpSync, writeFileSync} = require('fs')
+const basePkg = require('./package.json')
+
+const PACKAGES = [
+	'ffmpeg-static',
+	'ffprobe-static',
+]
+
+const copyFileIntoPackage = (pkgName, filename) => {
+	const src = pathJoin(__dirname, filename)
+	const dest = pathJoin(__dirname, 'packages', pkgName, filename)
+	cpSync(src, dest, {
+		dereference: true, // dereference symlinks
+		preserveTimestamps: true,
+	})
+}
+
+const generatePackageJsonForPackages = (pkgName) => {
+	const tplPath = pathJoin(__dirname, 'packages', pkgName, 'package.template.json')
+	const tpl = require(tplPath)
+
+	const packageJson = {
+		...basePkg,
+
+		// remove fields
+		private: undefined,
+		workspaces: undefined,
+		...Object.fromEntries(
+			PACKAGES
+			// remove own entry
+			.filter(_pkgName => _pkgName !== pkgName)
+			// remove others by setting `undefined` as value
+			.map(_pkgName => [_pkgName, undefined])
+		),
+
+		main: 'index.js',
+		files: [
+			'index.js',
+			'install.js',
+			'example.js',
+			'types',
+		],
+		types: 'types/index.d.ts',
+		scripts: {
+			install: 'node install.js',
+			prepublishOnly: 'npm run install',
+		},
+		devDependencies: {
+			...basePkg.devDependencies,
+			eslint: undefined, // remove field
+		},
+
+		...tpl,
+	}
+
+	const dest = pathJoin(__dirname, 'packages', pkgName, 'package.json')
+	writeFileSync(dest, JSON.stringify(packageJson, null, '\t'))
+}
+
+for (const pkgName of PACKAGES) {
+	copyFileIntoPackage(pkgName, 'LICENSE')
+	copyFileIntoPackage(pkgName, 'index.js')
+	copyFileIntoPackage(pkgName, 'install.js')
+	generatePackageJsonForPackages(pkgName)
+
+	console.info(pkgName, '✔︎')
+}

package.json

@@ -10,7 +10,8 @@
   "scripts": {
     "test": "node test.js",
     "lint": "eslint .",
-    "prepublishOnly": "npm run lint && npm install --workspaces && npm test"
+    "build": "./build-packages.js",
+    "prepublishOnly": "npm run lint && npm run build && npm install --workspaces && npm test"
   },
   "ffmpeg-static": {
     "binary-path-env-var": "FFMPEG_BIN",