diff --git a/src/core/create_compilers/extract_css.ts b/src/core/create_compilers/extract_css.ts
index 634da73..c5cf931 100644
--- a/src/core/create_compilers/extract_css.ts
+++ b/src/core/create_compilers/extract_css.ts
@@ -169,7 +169,7 @@ export default function extract_css(client_result: CompileResult, components: Pa
 		return null;
 	}
 
-	const main = client_result.assets.main;
+	let main = client_result.assets.main;
 	if (process.env.SAPPER_LEGACY_BUILD) main = `legacy/${main}`;
 	const entry = fs.readFileSync(`${dirs.dest}/client/${main}`, 'utf-8');