filter out .DS_Store and mp3s

site/src/service-worker.js

@@ -4,7 +4,12 @@ const ASSETS = `cache${timestamp}`;
 
 // `shell` is an array of all the files generated by Rollup,
 // `files` is an array of everything in the `static` directory
-const to_cache = shell.concat(files);
+const to_cache = shell.concat(files.filter(file => {
+	const basename = file.split('/').pop();
+	if (basename[0] === '.') return false; // .DS_Store and friends
+	if (basename.endsWith('.mp3')) return false; // TODO others?
+	return true;
+}));
 const cached = new Set(to_cache);
 
 self.addEventListener('install', event => {