From ff3d64f83cf70fac24c90fc3a867330f3bb1e252 Mon Sep 17 00:00:00 2001
From: Yui T <yuisu@microsoft.com>
Date: Tue, 2 Dec 2014 13:29:49 -0800
Subject: [PATCH] Address codereview

---
 src/compiler/emitter.ts | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 303ca6264cb..0a953877866 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -2197,22 +2197,29 @@ module ts {
                 emitTrailingComments(node);
             }
 
-            function emitShorthandPropertyAssignmentAsNormalPropertyAssignment(node: ShorthandPropertyDeclaration) {
+            function emitDownlevelShorthandPropertyAssignment(node: ShorthandPropertyDeclaration) {
                 emitLeadingComments(node);
                 // Emit identifier as an identifier
                 emit(node.name);
                 write(": ");
-                // Even though this is stored as identified because it is in short-hand property assignment,
-                // treated it as expression 
+                // Even though this is stored as identifier treat it as an expression
+                // Short-hand, { x }, is equivalent of normal form { x: x }
                 emitExpressionIdentifier(node.name);
                 emitTrailingComments(node);
             }
 
             function emitShorthandPropertyAssignment(node: ShorthandPropertyDeclaration) {
-                // If short-hand property has a prefix, then regardless of the target version, we will emit it as normal property assignment
+                // If short-hand property has a prefix, then regardless of the target version, we will emit it as normal property assignment. For example:
+                //  module m {
+                //      export var y;
+                //  }
+                //  module m {
+                //      export var obj = { y };
+                //  }
+                //  The short-hand property in obj need to emit as such ... = { y : m.y } regardless of the TargetScript version
                 var prefix = resolver.getExpressionNamePrefix(node.name);
                 if (prefix) {
-                    emitShorthandPropertyAssignmentAsNormalPropertyAssignment(node);
+                    emitDownlevelShorthandPropertyAssignment(node);
                 }
                 // If short-hand property has no prefix, emit it as short-hand.
                 else {
@@ -3408,7 +3415,7 @@ module ts {
                     return emitPinnedOrTripleSlashComments(node);
                 }
 
-                // Check if node has SyntaxKind which can be emitted regardless of the ScriptTarget
+                // Check if the node can be emitted regardless of the ScriptTarget
                 switch (node.kind) {
                     case SyntaxKind.Identifier:
                         return emitIdentifier(<Identifier>node);
@@ -3539,11 +3546,12 @@ module ts {
                     // Emit node down-level
                     switch (node.kind) {
                         case SyntaxKind.ShorthandPropertyAssignment:
-                            return emitShorthandPropertyAssignmentAsNormalPropertyAssignment(<ShorthandPropertyDeclaration>node);
+                            return emitDownlevelShorthandPropertyAssignment(<ShorthandPropertyDeclaration>node);
                     }
                 }
-                else if (compilerOptions.target >= ScriptTarget.ES6) {
+                else {
                     // Emit node natively
+                    Debug.assert(compilerOptions.target >= ScriptTarget.ES6, "Invalid ScriptTarget. We should emit as ES6 or above");
                     switch (node.kind) {
                         case SyntaxKind.ShorthandPropertyAssignment:
                             return emitShorthandPropertyAssignment(<ShorthandPropertyDeclaration>node);