From a11f72f9ab5de52b0f7c1bd7fdeb87489ae9e7f3 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 16 May 2016 13:34:54 -0700
Subject: [PATCH] Emit '?' for optional parameter property in declaration file

---
 src/compiler/declarationEmitter.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index aceec933227..a94c9a58d21 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -1129,7 +1129,7 @@ namespace ts {
                     // what we want, namely the name expression enclosed in brackets.
                     writeTextOfNode(currentText, node.name);
                     // If optional property emit ?
-                    if ((node.kind === SyntaxKind.PropertyDeclaration || node.kind === SyntaxKind.PropertySignature) && hasQuestionToken(node)) {
+                    if ((node.kind === SyntaxKind.PropertyDeclaration || node.kind === SyntaxKind.PropertySignature || node.kind === SyntaxKind.Parameter) && hasQuestionToken(node)) {
                         write("?");
                     }
                     if ((node.kind === SyntaxKind.PropertyDeclaration || node.kind === SyntaxKind.PropertySignature) && node.parent.kind === SyntaxKind.TypeLiteral) {