Augment escapeString to fix downlevel template literal emit.

src/compiler/core.ts

@@ -591,27 +591,44 @@ module ts {
         return path;
     }
 
-    var escapedCharsRegExp = /[\t\v\f\b\0\r\n\"\\\u2028\u2029\u0085]/g;
+    var backslashOrDoubleQuote = /[\"\\]/g;
+    var escapedCharsRegExp = /[\0-\19\t\v\f\b\0\r\n\u2028\u2029\u0085]/g;
     var escapedCharsMap: Map<string> = {
+        "\0": "\\0",
         "\t": "\\t",
         "\v": "\\v",
         "\f": "\\f",
         "\b": "\\b",
-        "\0": "\\0",
         "\r": "\\r",
         "\n": "\\n",
+        "\\": "\\\\",
         "\"": "\\\"",
         "\u2028": "\\u2028", // lineSeparator
         "\u2029": "\\u2029", // paragraphSeparator
         "\u0085": "\\u0085"  // nextLine
     };
 
-    /** NOTE: This *does not* support the full escape characters, it only supports the subset that can be used in file names
-      * or string literals. If the information encoded in the map changes, this needs to be revisited. */
+    /**
+     * Based heavily on the abstract 'Quote' operation from ECMA-262 (24.3.2.2),
+     * but augmented for a few select characters.
+     * Note that this doesn't actually wrap the input in double quotes.
+     */
     export function escapeString(s: string): string {
-        return escapedCharsRegExp.test(s) ? s.replace(escapedCharsRegExp, c => {
-            return escapedCharsMap[c] || c;
-        }) : s;
+        // Prioritize '"' and '\'
+        s = backslashOrDoubleQuote.test(s) ? s.replace(backslashOrDoubleQuote, getReplacement) : s;
+        s = escapedCharsRegExp.test(s) ? s.replace(escapedCharsRegExp, getReplacement) : s;
+
+        return s;
+
+        function getReplacement(c: string) {
+            return escapedCharsMap[c] || unicodeEscape(c);
+        }
+
+        function unicodeEscape(c: string): string {
+            var hexCharCode = c.charCodeAt(0).toString(16);
+            var paddedHexCode = ("0000" + hexCharCode).slice(-4);
+            return "\\u" + paddedHexCode;
+        }
     }
 
     export interface ObjectAllocator {

tests/baselines/reference/templateStringTermination2.js

@@ -3,4 +3,4 @@
 `\\`
 
 //// [templateStringTermination2.js]
-"\";
+"\\";

tests/baselines/reference/templateStringTermination4.js

@@ -3,4 +3,4 @@
 `\\\\`
 
 //// [templateStringTermination4.js]
-"\\";
+"\\\\";

tests/baselines/reference/templateStringTermination5.js

@@ -3,4 +3,4 @@
 `\\\\\\`
 
 //// [templateStringTermination5.js]
-"\\\";
+"\\\\\\";

tests/baselines/reference/templateStringWhitespaceEscapes1.js

@@ -0,0 +1,7 @@
+//// [templateStringWhitespaceEscapes1.ts]
+
+
+`\t\n\v\f\r`;
+
+//// [templateStringWhitespaceEscapes1.js]
+"\t\n\v\f\r";

tests/baselines/reference/templateStringWhitespaceEscapes1.types

@@ -0,0 +1,5 @@
+=== tests/cases/conformance/es6/templates/templateStringWhitespaceEscapes1.ts ===
+
+No type information for this code.
+No type information for this code.`\t\n\v\f\r`;
+No type information for this code.

tests/baselines/reference/templateStringWhitespaceEscapes1_ES6.js

@@ -0,0 +1,6 @@
+//// [templateStringWhitespaceEscapes1_ES6.ts]
+
+`\t\n\v\f\r`;
+
+//// [templateStringWhitespaceEscapes1_ES6.js]
+`\t\n\v\f\r`;

tests/baselines/reference/templateStringWhitespaceEscapes1_ES6.types

@@ -0,0 +1,4 @@
+=== tests/cases/conformance/es6/templates/templateStringWhitespaceEscapes1_ES6.ts ===
+
+No type information for this code.`\t\n\v\f\r`;
+No type information for this code.

tests/baselines/reference/templateStringWhitespaceEscapes2.js

@@ -0,0 +1,9 @@
+//// [templateStringWhitespaceEscapes2.ts]
+
+
+// <TAB>, <VT>, <FF>, <SP>, <NBSP>, <BOM>
+`\u0009\u000B\u000C\u0020\u00A0\uFEFF`;
+
+//// [templateStringWhitespaceEscapes2.js]
+// <TAB>, <VT>, <FF>, <SP>, <NBSP>, <BOM>
+"\t\v\f  ";

tests/baselines/reference/templateStringWhitespaceEscapes2.types

@@ -0,0 +1,6 @@
+=== tests/cases/conformance/es6/templates/templateStringWhitespaceEscapes2.ts ===
+
+No type information for this code.
+No type information for this code.// <TAB>, <VT>, <FF>, <SP>, <NBSP>, <BOM>
+No type information for this code.`\u0009\u000B\u000C\u0020\u00A0\uFEFF`;
+No type information for this code.

tests/baselines/reference/templateStringWhitespaceEscapes2_ES6.js

@@ -0,0 +1,8 @@
+//// [templateStringWhitespaceEscapes2_ES6.ts]
+
+// <TAB>, <VT>, <FF>, <SP>, <NBSP>, <BOM>
+`\u0009\u000B\u000C\u0020\u00A0\uFEFF`;
+
+//// [templateStringWhitespaceEscapes2_ES6.js]
+// <TAB>, <VT>, <FF>, <SP>, <NBSP>, <BOM>
+`\u0009\u000B\u000C\u0020\u00A0\uFEFF`;

tests/baselines/reference/templateStringWhitespaceEscapes2_ES6.types

@@ -0,0 +1,5 @@
+=== tests/cases/conformance/es6/templates/templateStringWhitespaceEscapes2_ES6.ts ===
+
+No type information for this code.// <TAB>, <VT>, <FF>, <SP>, <NBSP>, <BOM>
+No type information for this code.`\u0009\u000B\u000C\u0020\u00A0\uFEFF`;
+No type information for this code.

tests/cases/conformance/es6/templates/templateStringWhitespaceEscapes1.ts

@@ -0,0 +1,3 @@
+
+
+`\t\n\v\f\r`;

tests/cases/conformance/es6/templates/templateStringWhitespaceEscapes1_ES6.ts

@@ -0,0 +1,3 @@
+//@target: es6
+
+`\t\n\v\f\r`;

tests/cases/conformance/es6/templates/templateStringWhitespaceEscapes2.ts

@@ -0,0 +1,4 @@
+
+
+// <TAB>, <VT>, <FF>, <SP>, <NBSP>, <BOM>
+`\u0009\u000B\u000C\u0020\u00A0\uFEFF`;

tests/cases/conformance/es6/templates/templateStringWhitespaceEscapes2_ES6.ts

@@ -0,0 +1,4 @@
+//@target: es6
+
+// <TAB>, <VT>, <FF>, <SP>, <NBSP>, <BOM>
+`\u0009\u000B\u000C\u0020\u00A0\uFEFF`;