diff --git a/src/uglifyjs.ts b/src/uglifyjs.ts
index fe7bda0a..83667bbd 100644
--- a/src/uglifyjs.ts
+++ b/src/uglifyjs.ts
@@ -47,7 +47,6 @@ export async function uglifyjsWorkerImpl(context: BuildContext, uglifyJsConfig:
 }
 
 async function runUglifyInternal(sourceFilePath: string, destFilePath: string, sourceMapPath: string, destMapPath: string, configObject: any): Promise<any> {
-  const sourceFileContentPromise = readFileAsync(sourceFilePath);
   const [sourceFileContent, sourceMapContent] = await Promise.all([readFileAsync(sourceFilePath), readFileAsync(sourceMapPath)]);
   const uglifyConfig = Object.assign({}, configObject, {
     sourceMap: {