if index >= length, output notifications

background.js

 'use strict';
-var initial = 0;
+var index = 0;
 var skus = [];
 var noImages = "";
 
@@ -19,22 +19,21 @@ chrome.extension.onMessage.addListener(function(request,sender,sendResponse){
     console.log(skus);
   } else if(request.nothing == "true") {
     console.log("Message : nothing ");
-    noImages += (request.currentSku + ": no duplicate files\n");
-    initial++;
+    index++;
   } else if(request.noImage == "true") {
     console.log("Message : noImages"); 
     noImages += (request.currentSku + ": no results/ no valid images\n");
-    initial += 2;
+    index += 2;
   }
-  console.log("Current index : ", initial);
+  console.log("Current index : ", index);
   console.log("Current noImages : " , noImages);
 });
 
 chrome.downloads.onDeterminingFilename.addListener(function(item, suggest) {
-  var new_filename = skus[initial] + ".zip"; 
+  var new_filename = skus[index] + ".zip"; 
   suggest({filename: new_filename});
-  initial++;
-  if(skus.length-1 == initial) {
+  index++;
+  if(index >= skus.length-1) {
     console.log("Last file was downloaded");
     alert(noImages);
   }