rewrite in node.js 6-compatible commonjs

.prettierrc.yaml

@@ -1,3 +0,0 @@
-useTabs: true
-singleQuote: true
-trailingComma: es5

index.js

@@ -0,0 +1,26 @@
+const fs = require('fs');
+
+const readText = filename => new Promise(res => fs.readFile(filename, (err, data) => (err ? res(null) : res(data.toString()))));
+
+module.exports = ({ extensions = ['.html', '.svelte'] } = {}) => ({
+	transform: (code, id) => {
+		const extension = extensions.find(extension => id.endsWith(extension));
+		if (extension) {
+			const baseId = id.slice(0, -extension.length);
+			const jsId = baseId + '.js';
+			const cssId = baseId + '.css';
+			return Promise.all([jsId, cssId].map(readText)).then(([js, css]) => {
+				const dependencies = [];
+				if (js) {
+					dependencies.push(jsId);
+					code += `\n<script>\n${js}\n</script>\n`;
+				}
+				if (css) {
+					dependencies.push(cssId);
+					code += `\n<style>\n${css}\n</style>\n`;
+				}
+				return { code, dependencies };
+			});
+		}
+	},
+});

src/svelte-combiner.js

@@ -1,32 +0,0 @@
-import { readFile } from 'fs';
-
-const readText = filename =>
-	new Promise(res =>
-		readFile(filename, (err, data) => (err ? res(null) : res(data.toString())))
-	);
-
-export default function svelteCombiner({
-	extensions = ['.html', '.svelte'],
-} = {}) {
-	return {
-		transform: async (code, id) => {
-			const extension = extensions.find(extension => id.endsWith(extension));
-			if (extension) {
-				const baseId = id.slice(0, -extension.length);
-				const jsId = baseId + '.js';
-				const cssId = baseId + '.css';
-				const [js, css] = await Promise.all([jsId, cssId].map(readText));
-				const dependencies = [];
-				if (js) {
-					dependencies.push(jsId);
-					code += `\n<script>\n${js}\n</script>\n`;
-				}
-				if (css) {
-					dependencies.push(cssId);
-					code += `\n<style>\n${css}\n</style>\n`;
-				}
-				return { code, dependencies };
-			}
-		},
-	};
-}