fix(addCORSHeaders): add Access-Control-Expose-Headers for custom headers

Author: coderbyheart

src/addCORSHeaders.ts

@@ -6,6 +6,11 @@ import type {
 
 export const addCORSHeaders = (
 	AccessControlAllowOrigin: string = '*',
+	AccessControlExposeHeaders: Array<string> = [
+		'x-amzn-requestid',
+		'etag',
+		'apigw-requestid',
+	],
 ): MiddlewareObj<APIGatewayProxyEventV2, APIGatewayProxyStructuredResultV2> => {
 	const setCORSHeaders = async (req: Request) => {
 		if (req.response === null) return
@@ -14,6 +19,7 @@ export const addCORSHeaders = (
 			headers: {
 				...(req.response.headers ?? {}),
 				'Access-Control-Allow-Origin': AccessControlAllowOrigin,
+				'Access-Control-Expose-Headers': AccessControlExposeHeaders.join(', '),
 			},
 		}
 	}