fix output file not saved (CLI) (fix #556)

cli/single-file-cli-api.js

@@ -203,9 +203,9 @@ async function capturePage(options) {
 	try {
 		const pageData = await backend.getPageData(options);
 		if (options.output) {
-			const filename = getFilename(pageData.output, options);
+			const filename = getFilename(options.output, options);
 			if (filename) {
-				fs.writeFileSync(options.output, pageData.content);
+				fs.writeFileSync(filename, pageData.content);
 			}
 		} else {
 			const filename = getFilename(pageData.filename, options);