give manifest searching a function

index.mjs

@@ -46,6 +46,8 @@ export function createConfig (manifestPathRelative, options, createConfig) {
 		return join(outputDir, platform, getOutputFilename(entryPath, ext));
 	}
 
+	/** Scans a manifest for entrypoints */
+	function getEntryPointsFromManifest (manifestContent) {
 		const scriptEntrypointAbsolutePaths = [];
 		const styleEntrypointAbsolutePathss = [];
 		const otherAssetAbsolutePaths = [];
@@ -95,9 +97,18 @@ export function createConfig (manifestPathRelative, options, createConfig) {
 			}
 		});
 
+		return {
+			scripts: scriptEntrypointAbsolutePaths,
+			styles: styleEntrypointAbsolutePathss,
+			assets: otherAssetAbsolutePaths,
+		};
+	}
+
+	const {scripts, styles, assets} = getEntryPointsFromManifest(manifestContent);
+
 	const platform = 'firefox';
 	return [
-		...scriptEntrypointAbsolutePaths.map(entrypointPath => ({
+		...scripts.map(entrypointPath => ({
 			// Get configuration options for this entrypoint from the caller
 			...createConfig(),
 			// Overwrite input and output options
@@ -119,14 +130,14 @@ export function createConfig (manifestPathRelative, options, createConfig) {
 			plugins: [
 				{
 					buildStart () {
-						styleEntrypointAbsolutePathss.forEach(absolutePath => {
+						styles.forEach(absolutePath => {
 							this.emitFile({
 								type: 'asset',
 								fileName: getOutputFilename(absolutePath, 'css'),
 								source: readFileSync(absolutePath, {encoding: 'utf-8'}),
 							});
 						});
-						otherAssetAbsolutePaths.forEach(absolutePath => {
+						assets.forEach(absolutePath => {
 							// console.log('rendering binary file', absolutePath);
 							this.emitFile({
 								type: 'asset',