Adopt lerna and typescript

packages/ffmpeg/src/browser/defaultOptions.js

@@ -0,0 +1,10 @@
+import pkg from '../../package.json';
+
+/*
+ * Default options for browser environment
+ */
+const corePath = typeof process !== 'undefined' && process.env.NODE_ENV === 'development'
+  ? new URL('/node_modules/@ffmpeg/core/dist/ffmpeg-core.js', import.meta.url).href
+  : `https://unpkg.com/@ffmpeg/core@${pkg.devDependencies['@ffmpeg/core'].substring(1)}/dist/ffmpeg-core.js`;
+
+export default { corePath };