From fa5da68e7d03232cdc6bfd77533c97b203c0a5e3 Mon Sep 17 00:00:00 2001
From: Adrian Leonhard <adrianleonhard@gmail.com>
Date: Mon, 25 Sep 2017 00:10:54 +0200
Subject: [PATCH] type WriteFileCallback: make param sourceFiles required.

Fixes https://github.com/Microsoft/TypeScript/issues/15007
---
 src/compiler/types.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 4e5ca9f07e77f..7a120064a64cb 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2442,7 +2442,7 @@ namespace ts {
     }
 
     export interface WriteFileCallback {
-        (fileName: string, data: string, writeByteOrderMark: boolean, onError?: (message: string) => void, sourceFiles?: ReadonlyArray<SourceFile>): void;
+        (fileName: string, data: string, writeByteOrderMark: boolean, onError: ((message: string) => void) | undefined, sourceFiles: ReadonlyArray<SourceFile>): void;
     }
 
     export class OperationCanceledException { }