added a test and fixed some bugs. yay!

forEachAsync.js

@@ -8,15 +8,16 @@
       ;
 
     function next(BREAK, newArr) {
-      if (0 === arr.length || BREAK === forEachAsync.__BREAK) {
+      index += 1;
+
+      if (index === arr.length || BREAK === forEachAsync.__BREAK) {
         dones.forEach(function (done) {
           done.call(thisArg, newArr);
         });
         return;
       }
 
-      index += 1;
-      fn.call(thisArg, next, arr.shift(), index, arr);
+      fn.call(thisArg, next, arr[index], index, arr);
     }
 
     setTimeout(next, 4);

test.js

@@ -0,0 +1,15 @@
+(function () {
+  "use strict";
+
+  var forEachAsync = require('../forEachAsync').forEachAsync
+    ;
+
+  forEachAsync([0, 500, 70, 800], function (next, element, i, arr) {
+    console.log(element, 'is element', i, 'of', arr.length);
+    this[element] = i;
+    setTimeout(next, element);
+  }, {}).then(function () {
+    console.log(this);
+  });
+
+}());