Properly parse unicode characters in strings

This fixes the parsing of unicode strings that are 1 or 6
hex characters long.

Extends the tests to support a third element in examples, which
would be the re-stringified example, since a unicode character might
be stringified in a different way than the original code, and still be
valid.

fixes webpack/css-loader#133
fixes #12

Author: pieter

lib/parseValues.js

@@ -23,17 +23,17 @@ function endSpacingMatch(match) {
 }
 
 function unescapeString(content) {
-	return content.replace(/\\([a-fA-F0-9]{2,5}|.)/g, function(escaped) {
-		if(escaped.length > 2) {
-			var C = parseInt(escaped.substr(1), 16);
-			if(C < 0x10000) {
-				return String.fromCharCode(C);
-			} else {
-				return String.fromCharCode(Math.floor((C - 0x10000) / 0x400) + 0xD800) +
-					String.fromCharCode((C - 0x10000) % 0x400 + 0xDC00);
-			}
+	return content.replace(/\\(?:([a-fA-F0-9]{1,6})|(.))/g, function(all, unicode, otherCharacter) {
+		if (otherCharacter) {
+			return otherCharacter;
+		}
+
+		var C = parseInt(unicode, 16);
+		if(C < 0x10000) {
+			return String.fromCharCode(C);
 		} else {
-			return escaped.substr(1);
+			return String.fromCharCode(Math.floor((C - 0x10000) / 0x400) + 0xD800) +
+				String.fromCharCode((C - 0x10000) % 0x400 + 0xDC00);
 		}
 	});
 }

test/stringifyValues.js

@@ -10,7 +10,7 @@ describe("stringifyValues", function() {
 	Object.keys(testCases).forEach(function(testCase) {
 		it("should stringify values " + testCase, function() {
 			var input = testCases[testCase][1];
-			var expected = testCases[testCase][0];
+			var expected = testCases[testCase][2] || testCases[testCase][0];
 			assert.deepEqual(Tokenizer.stringifyValues(input), expected);
 		});
 	});

test/test-cases-values.js

@@ -175,7 +175,20 @@ module.exports = {
 		"\"\\1F50E\"",
 		singleValue([
 			{ type: "string", stringType: "\"", value: "\ud83d\udd0e" }
-		])
+		]),
+  ],
+	"escaped unicode 5 (extra short)": [
+		"\"\\A\"",
+		singleValue([
+			{ type: "string", stringType: "\"", value: "\u000A" }
+		]),
+	],
+	"escaped unicode 6 (full length)": [
+		"\"\\00000A\"",
+		singleValue([
+			{ type: "string", stringType: "\"", value: "\u000A" }
+		]),
+		"\"\\A\""
 	],
 	"nested-item-with append": [
 		"linear-gradient(45deg) 25%",