Emit all strings with extended escapes using the same scheme as templates.

src/compiler/emitter.ts

@@ -2187,9 +2187,12 @@ module ts {
             }
 
             function emitLiteral(node: LiteralExpression) {
-                var text = languageVersion < ScriptTarget.ES6 && isTemplateLiteralKind(node.kind) ? getTemplateLiteralAsStringLiteral(node) :
-                    node.parent ? getSourceTextOfNodeFromSourceFile(currentSourceFile, node) :
-                        node.text;
+                var text = languageVersion < ScriptTarget.ES6 && (isTemplateLiteralKind(node.kind) || node.hasExtendedUnicodeEscape)
+                    ? getDoubleQuotedStringTextOfLiteral(node)
+                    : node.parent
+                        ? getSourceTextOfNodeFromSourceFile(currentSourceFile, node)
+                        : node.text; // TODO(drosen): Is this correct?
+                
                 if (compilerOptions.sourceMap && (node.kind === SyntaxKind.StringLiteral || isTemplateLiteralKind(node.kind))) {
                     writer.writeLiteral(text);
                 }
@@ -2202,7 +2205,7 @@ module ts {
                 }
             }
             
-            function getTemplateLiteralAsStringLiteral(node: LiteralExpression): string {
+            function getDoubleQuotedStringTextOfLiteral(node: LiteralExpression): string {
                 var result = escapeString(node.text);
                 result = replaceNonAsciiCharacters(result);
                 

src/compiler/parser.ts

@@ -2164,6 +2164,10 @@ module ts {
             var text = scanner.getTokenValue();
             node.text = internName ? internIdentifier(text) : text;
 
+            if (scanner.hasExtendedUnicodeEscape()) {
+                node.hasExtendedUnicodeEscape = true;
+            }
+            
             if (scanner.isUnterminated()) {
                 node.isUnterminated = true;
             }

src/compiler/scanner.ts

@@ -14,6 +14,7 @@ module ts {
         getTokenPos(): number;
         getTokenText(): string;
         getTokenValue(): string;
+        hasExtendedUnicodeEscape(): boolean;
         hasPrecedingLineBreak(): boolean;
         isIdentifier(): boolean;
         isReservedWord(): boolean;
@@ -556,6 +557,7 @@ module ts {
         var token: SyntaxKind;
         var tokenValue: string;
         var precedingLineBreak: boolean;
+        var hasExtendedUnicodeEscape: boolean;
         var tokenIsUnterminated: boolean;
 
         function error(message: DiagnosticMessage, length?: number): void {
@@ -776,6 +778,7 @@ module ts {
                     return "\"";
                 case CharacterCodes.u:
                     if (text.charCodeAt(pos) === CharacterCodes.openBrace) {
+                        hasExtendedUnicodeEscape = true;
                         pos++;
                         var escapedValue = scanMinimumNumberOfHexDigits(1);
                         
@@ -926,6 +929,7 @@ module ts {
 
         function scan(): SyntaxKind {
             startPos = pos;
+            hasExtendedUnicodeEscape = false;
             precedingLineBreak = false;
             tokenIsUnterminated = false;
             while (true) {
@@ -1393,6 +1397,7 @@ module ts {
             getTokenPos: () => tokenPos,
             getTokenText: () => text.substring(tokenPos, pos),
             getTokenValue: () => tokenValue,
+            hasExtendedUnicodeEscape: () => hasExtendedUnicodeEscape,
             hasPrecedingLineBreak: () => precedingLineBreak,
             isIdentifier: () => token === SyntaxKind.Identifier || token > SyntaxKind.LastReservedWord,
             isReservedWord: () => token >= SyntaxKind.FirstReservedWord && token <= SyntaxKind.LastReservedWord,

src/compiler/types.ts

@@ -655,6 +655,7 @@ module ts {
     export interface LiteralExpression extends PrimaryExpression {
         text: string;
         isUnterminated?: boolean;
+        hasExtendedUnicodeEscape?: boolean;
     }
 
     export interface StringLiteralExpression extends LiteralExpression {