diff --git a/package.json b/package.json
index 8153c2c..127dfff 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,6 @@
   ],
   "scripts": {
     "prepublishOnly": "npm run build",
-    "postinstall": "npm run build",
     "precommit": "npm run lint",
     "build": "npm run clean && tsc",
     "clean": "rm -rf ./dist",
diff --git a/src/function.ts b/src/function.ts
index 0201a8c..c5e9b67 100644
--- a/src/function.ts
+++ b/src/function.ts
@@ -30,7 +30,7 @@ export class NodejsFunction extends lambda.Function {
 
     const withDefaultOptions = mergeRight(DEFAULT_BUILD_OPTIONS);
     const buildOptions = withDefaultOptions<es.BuildOptions>(props.esbuildOptions ?? {});
-    const exclude = union(props.exclude || [], ['aws-sdk']);
+    const exclude = props.exclude ?? ['aws-sdk'];
     const packager = props.packager ?? true;
     const handler = props.handler ?? 'index.handler';
     const defaultRuntime = nodeMajorVersion() >= 12