Make multiLine optional in convertToFunctionBody

Author: rbuckton

src/compiler/factory.ts

@@ -2343,11 +2343,11 @@ namespace ts {
         return qualifiedName;
     }
 
-    export function convertToFunctionBody(node: ConciseBody) {
+    export function convertToFunctionBody(node: ConciseBody, multiLine?: boolean) {
         if (isBlock(node)) {
             return node;
         }
-        return createBlock([createReturn(node, node)], node, /*multiLine*/ true);
+        return createBlock([createReturn(node, node)], node, multiLine);
     }
 
     function isUseStrictPrologue(node: ExpressionStatement): boolean {

src/compiler/transformers/esnext.ts

@@ -363,14 +363,12 @@ namespace ts {
                     }
                 }
             }
-
             const body = visitNode(node.body, visitor, isConciseBody);
             const trailingStatements = endLexicalEnvironment();
             if (some(leadingStatements) || some(trailingStatements)) {
-                const block = convertToFunctionBody(body);
+                const block = convertToFunctionBody(body, /*multiLine*/ true);
                 return updateBlock(block, createNodeArray(concatenate(concatenate(leadingStatements, block.statements), trailingStatements), block.statements));
             }
-
             return body;
         }
     }