use Rollup

rollup/service-worker.config.js

@@ -0,0 +1,27 @@
+import resolve from 'rollup-plugin-node-resolve';
+import replace from 'rollup-plugin-replace';
+import commonjs from 'rollup-plugin-commonjs';
+import { terser } from 'rollup-plugin-terser';
+import config from 'sapper/config/rollup.js';
+
+const mode = process.env.NODE_ENV;
+const dev = mode === 'development';
+
+export default {
+	input: config.serviceworker.input(),
+	output: config.serviceworker.output(),
+	plugins: [
+		resolve(),
+		replace({
+			'process.browser': true,
+			'process.env.NODE_ENV': JSON.stringify(mode)
+		}),
+		commonjs(),
+		!dev && terser()
+	],
+
+	// temporary, pending https://github.com/rollup/rollup/pull/2432
+	watch: {
+		chokidar: { disableGlobbing: true }
+	}
+};