Scanner returns empty string if it can't match

mustache.js

@@ -114,7 +114,7 @@ var Mustache;
 
   /**
    * Tries to match the given regular expression at the current position.
-   * Returns the matched text if it can match, `null` otherwise.
+   * Returns the matched text if it can match, the empty string otherwise.
    */
   Scanner.prototype.scan = function (re) {
     var match = this.tail.match(re);
@@ -125,13 +125,12 @@ var Mustache;
       return match[0];
     }
 
-    return null;
+    return "";
   };
 
   /**
    * Skips all text until the given regular expression can be matched. Returns
-   * the skipped string, which is the entire tail of this scanner if no match
-   * can be made.
+   * the skipped string, which is the entire tail if no match can be made.
    */
   Scanner.prototype.scanUntil = function (re) {
     var match, pos = this.tail.search(re);
@@ -143,7 +142,7 @@ var Mustache;
       this.tail = "";
       break;
     case 0:
-      match = null;
+      match = "";
       break;
     default:
       match = this.tail.substring(0, pos);

test/scanner_test.js

@@ -47,8 +47,8 @@ vows.describe("Mustache.Scanner").addBatch({
               var match = scanner.scan(/b/);
               this.callback(scanner, match);
             },
-            "it should return null": function (scanner, match) {
-              assert.equal(match, null);
+            "it should return the empty string": function (scanner, match) {
+              assert.equal(match, "");
             },
             "it should not advance the internal pointer": function (scanner, match) {
               assert.equal(scanner.pos, 0);
@@ -61,8 +61,8 @@ vows.describe("Mustache.Scanner").addBatch({
             var match = scanner.scan(/z/);
             this.callback(scanner, match);
           },
-          "it should return null": function (scanner, match) {
-            assert.equal(match, null);
+          "it should return the empty string": function (scanner, match) {
+            assert.equal(match, "");
           },
           "it should not advance the internal pointer": function (scanner, match) {
             assert.equal(scanner.pos, 0);
@@ -77,8 +77,8 @@ vows.describe("Mustache.Scanner").addBatch({
               var match = scanner.scanUntil(/a/);
               this.callback(scanner, match);
             },
-            "it should return null": function (scanner, match) {
-              assert.equal(match, null)
+            "it should return the empty string": function (scanner, match) {
+              assert.equal(match, "")
             },
             "it should not advance the internal pointer": function (scanner, match) {
               assert.equal(scanner.pos, 0);