Added the logic to handle when array is null.

spec/KiwiSpec.js

@@ -1,10 +1,10 @@
 describe('Kiwi.compose', function() {
-    it('should return the empty when input is empty',function() {
+    it('should return the empty string when input is empty',function() {
         var input = "";
         expect(Kiwi.compose(input)).toEqual(input);
     });
 
-    it('should return the input string',function() {
+    it('should return the input string when array is null',function() {
         var input = "text without interpolation";
         expect(Kiwi.compose(input)).toEqual(input);
     });
@@ -44,4 +44,10 @@ describe('Kiwi.compose', function() {
         var result = "The rate is 2.3%";
         expect(Kiwi.compose(input, ["rate"])).toEqual(result);
     });
+
+    it('should add empty string when size of the array is larger than the placeholders.', function() {
+        var input = "The quick brown % jumps % the lazy %.";
+        var result = "The quick brown fox jumps over the lazy .";
+        expect(Kiwi.compose(input, ["fox", "over"])).toEqual(result);
+    });
 });

src/Kiwi.js

@@ -2,9 +2,12 @@ var Kiwi = (function ($) {
 	var TRANSPOSE_CHAR = '%';
 
 	var interpolate = function(text, array){
+		if(array === undefined) return text;
+
 		var stringToReturn = ""
 		 	,length = text.length
-		 	,index = 0;
+		 	,index = 0
+		 	,array_length = array.length;
 
 		for(var i = 0; i < length; i++){
 			var currentChar = text[i];
@@ -16,7 +19,11 @@ var Kiwi = (function ($) {
 				i += 1;
 			}else{
 				if(currentChar === TRANSPOSE_CHAR){
-					stringToReturn += array[index++];
+					if(index < array_length){
+						stringToReturn += array[index++];
+					}else{
+						stringToReturn += '';
+					}
 				}
 				else{
 					stringToReturn += currentChar;