diff --git a/dist/json-patch-duplex.min.js b/dist/json-patch-duplex.min.js
index b5b12af0..57c6ee6c 100644
--- a/dist/json-patch-duplex.min.js
+++ b/dist/json-patch-duplex.min.js
@@ -1,7 +1,7 @@
 /*!
-* https://github.com/Starcounter-Jack/JSON-Patch
-* json-patch-duplex.js version: 0.5.5
-* (c) 2013 Joachim Wester
-* MIT license
-*/
-var __extends=this.__extends||function(a,b){function c(){this.constructor=a}for(var d in b)b.hasOwnProperty(d)&&(a[d]=b[d]);c.prototype=b.prototype,a.prototype=new c},OriginalError=Error,jsonpatch;!function(a){function b(a,c){switch(typeof a){case"undefined":case"boolean":case"string":case"number":return a===c;case"object":if(null===a)return null===c;if(y(a)){if(!y(c)||a.length!==c.length)return!1;for(var d=0,e=a.length;e>d;d++)if(!b(a[d],c[d]))return!1;return!0}var f=r(c),g=f.length;if(r(a).length!==g)return!1;for(var d=0;g>d;d++)if(!b(a[d],c[d]))return!1;return!0;default:return!1}}function c(a){return-1===a.indexOf("/")&&-1===a.indexOf("~")?a:a.replace(/~/g,"~0").replace(/\//g,"~1")}function d(a){for(var b=0,c=v.length;c>b;b++)if(v[b].obj===a)return v[b]}function e(a,b){for(var c=0,d=a.observers.length;d>c;c++)if(a.observers[c].callback===b)return a.observers[c].observer}function f(a,b){for(var c=0,d=a.observers.length;d>c;c++)if(a.observers[c].observer===b)return void 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not an object","OPERATION_NOT_AN_OBJECT",c,b,d);if(!s[b.op])throw new z("Operation `op` property is not one of operations defined in RFC-6902","OPERATION_OP_INVALID",c,b,d);if("string"!=typeof b.path)throw new z("Operation `path` property is not a string","OPERATION_PATH_INVALID",c,b,d);if(("move"===b.op||"copy"===b.op)&&"string"!=typeof b.from)throw new z("Operation `from` property is not present (applicable in `move` and `copy` operations)","OPERATION_FROM_REQUIRED",c,b,d);if(("add"===b.op||"replace"===b.op||"test"===b.op)&&void 0===b.value)throw new z("Operation `value` property is not present (applicable in `add`, `replace` and `test` operations)","OPERATION_VALUE_REQUIRED",c,b,d);if(("add"===b.op||"replace"===b.op||"test"===b.op)&&o(b.value))throw new z("Operation `value` property is not present (applicable in `add`, `replace` and `test` operations)","OPERATION_VALUE_CANNOT_CONTAIN_UNDEFINED",c,b,d);if(d)if("add"==b.op){var f=b.path.split("/").length,g=e.split("/").length;if(f!==g+1&&f!==g)throw new z("Cannot perform an `add` operation at the desired path","OPERATION_PATH_CANNOT_ADD",c,b,d)}else if("replace"===b.op||"remove"===b.op||"_get"===b.op){if(b.path!==e)throw new z("Cannot perform the operation at a path that does not exist","OPERATION_PATH_UNRESOLVABLE",c,b,d)}else if("move"===b.op||"copy"===b.op){var h={op:"_get",path:b.from,value:void 0},i=a.validate([h],d);if(i&&"OPERATION_PATH_UNRESOLVABLE"===i.name)throw new z("Cannot perform the operation from a path that does not exist","OPERATION_FROM_UNRESOLVABLE",c,b,d)}}function q(a,b){try{if(!y(a))throw new z("Patch sequence must be an array","SEQUENCE_NOT_AN_ARRAY");if(b)b=JSON.parse(JSON.stringify(b)),m.call(this,b,a,!0);else for(var c=0;c<a.length;c++)this.validator(a[c],c)}catch(d){if(d instanceof z)return d;throw d}}if(!a.observe){var r=function(a){if(y(a))return Array.apply(null,{length:a.length}).map(function(a,b,c){return b.toString()});if(Object.keys)return Object.keys(a);var b=[];for(var c in a)a.hasOwnProperty(c)&&b.push(c);return b},s={add:function(a,b){return a[b]=this.value,!0},remove:function(a,b){return delete a[b],!0},replace:function(a,b){return a[b]=this.value,!0},move:function(a,b,c){var d={op:"_get",path:this.from};return m(c,[d]),m(c,[{op:"remove",path:this.from}]),m(c,[{op:"add",path:this.path,value:d.value}]),!0},copy:function(a,b,c){var d={op:"_get",path:this.from};return m(c,[d]),m(c,[{op:"add",path:this.path,value:d.value}]),!0},test:function(a,c){return b(a[c],this.value)},_get:function(a,b){this.value=a[b]}},t={add:function(a,b){return a.splice(b,0,this.value),!0},remove:function(a,b){return a.splice(b,1),!0},replace:function(a,b){return a[b]=this.value,!0},move:s.move,copy:s.copy,test:s.test,_get:s._get},u={add:function(a){u.remove.call(this,a);for(var b in this.value)this.value.hasOwnProperty(b)&&(a[b]=this.value[b]);return!0},remove:function(a){for(var b in a)a.hasOwnProperty(b)&&s.remove.call(this,a,b);return!0},replace:function(a){return m(a,[{op:"remove",path:this.path}]),m(a,[{op:"add",path:this.path,value:this.value}]),!0},move:s.move,copy:s.copy,test:function(a){return JSON.stringify(a)===JSON.stringify(this.value)},_get:function(a){this.value=a}},v=[];a.intervals;var w=function(){function a(a){this.observers=[],this.obj=a}return a}(),x=function(){function a(a,b){this.callback=a,this.observer=b}return a}();a.unobserve=g,a.observe=i,a.generate=j;var y;y=Array.isArray?Array.isArray:function(a){return a.push&&"number"==typeof a.length},a.apply=m,a.compare=n;var z=function(a){function b(b,c,d,e,f){a.call(this,b),this.message=b,this.name=c,this.index=d,this.operation=e,this.tree=f}return __extends(b,a),b}(OriginalError);a.JsonPatchError=z,a.Error=z,a.validator=p,a.validate=q}}(jsonpatch||(jsonpatch={})),"undefined"!=typeof exports&&(exports.apply=jsonpatch.apply,exports.observe=jsonpatch.observe,exports.unobserve=jsonpatch.unobserve,exports.generate=jsonpatch.generate,exports.compare=jsonpatch.compare,exports.validate=jsonpatch.validate,exports.validator=jsonpatch.validator,exports.JsonPatchError=jsonpatch.JsonPatchError,exports.Error=jsonpatch.Error);
\ No newline at end of file
+ * https://github.com/Starcounter-Jack/JSON-Patch
+ * json-patch-duplex.js version: 0.5.5
+ * (c) 2013 Joachim Wester
+ * MIT license
+ */
+var __extends=this&&this.__extends||function(a,b){function c(){this.constructor=a}for(var d in b)b.hasOwnProperty(d)&&(a[d]=b[d]);a.prototype=null===b?Object.create(b):(c.prototype=b.prototype,new c)},OriginalError=Error,jsonpatch;!function(a){function b(a,c){switch(typeof a){case"undefined":case"boolean":case"string":case"number":return a===c;case"object":if(null===a)return null===c;if(y(a)){if(!y(c)||a.length!==c.length)return!1;for(var d=0,e=a.length;e>d;d++)if(!b(a[d],c[d]))return!1;return!0}var f=r(c),g=f.length;if(r(a).length!==g)return!1;for(var d=0;g>d;d++)if(!b(a[d],c[d]))return!1;return!0;default:return!1}}function c(a){return-1===a.indexOf("/")&&-1===a.indexOf("~")?a:a.replace(/~/g,"~0").replace(/\//g,"~1")}function d(a){for(var b=0,c=v.length;c>b;b++)if(v[b].obj===a)return v[b]}function e(a,b){for(var c=0,d=a.observers.length;d>c;c++)if(a.observers[c].callback===b)return a.observers[c].observer}function f(a,b){for(var c=0,d=a.observers.length;d>c;c++)if(a.observers[c].observer===b)return void a.observers.splice(c,1)}function g(a,b){j(b),clearTimeout(b.next);var c=d(a);f(c,b)}function h(a){return"object"==typeof a?JSON.parse(JSON.stringify(a)):a}function i(a,b){var c,f=[],g=d(a);if(g?c=e(g,b):(g=new w(a),v.push(g)),c)return c;if(c={},g.value=h(a),b){c.callback=b,c.next=null;var i=this.intervals||[100,1e3,1e4,6e4];if(void 0===i.push)throw new OriginalError("jsonpatch.intervals must be an array");var k=0,l=function(){j(c)},m=function(){clearTimeout(c.next),c.next=setTimeout(function(){l(),k=0,c.next=setTimeout(n,i[k++])},0)},n=function(){l(),k==i.length&&(k=i.length-1),c.next=setTimeout(n,i[k++])};"undefined"!=typeof window&&(window.addEventListener?(window.addEventListener("mousedown",m),window.addEventListener("mouseup",m),window.addEventListener("keydown",m)):(document.documentElement.attachEvent("onmousedown",m),document.documentElement.attachEvent("onmouseup",m),document.documentElement.attachEvent("onkeydown",m))),c.next=setTimeout(n,i[k++])}return c.patches=f,c.object=a,g.observers.push(new x(b,c)),c}function j(a){for(var b,c=0,d=v.length;d>c;c++)if(v[c].obj===a.object){b=v[c];break}k(b.value,a.object,a.patches,""),a.patches.length&&m(b.value,a.patches);var e=a.patches;return e.length>0&&(a.patches=[],a.callback&&a.callback(e)),e}function k(a,b,d,e){for(var f=r(b),g=r(a),i=!1,j=!1,l=g.length-1;l>=0;l--){var m=g[l],n=a[m];if(b.hasOwnProperty(m)){var o=b[m];"object"==typeof n&&null!=n&&"object"==typeof o&&null!=o?k(n,o,d,e+"/"+c(m)):n!=o&&(i=!0,d.push({op:"replace",path:e+"/"+c(m),value:h(o)}))}else d.push({op:"remove",path:e+"/"+c(m)}),j=!0}if(j||f.length!=g.length)for(var l=0;l<f.length;l++){var m=f[l];a.hasOwnProperty(m)||d.push({op:"add",path:e+"/"+c(m),value:h(b[m])})}}function l(a){for(var b,c=0,d=a.length;d>c;){b=a.charCodeAt(c);{if(!(b>=48&&57>=b))return!1;c++}}return!0}function m(a,b,c){for(var d,e,f=!1,g=0,h=b.length;h>g;){d=b[g],g++;for(var i=d.path||"",j=i.split("/"),k=a,m=1,n=j.length,o=void 0;;){if(e=j[m],c&&void 0===o&&(void 0===k[e]?o=j.slice(0,m).join("/"):m==n-1&&(o=d.path),void 0!==o&&this.validator(d,g-1,a,o)),m++,void 0===e&&m>=n){f=u[d.op].call(d,k,e,a);break}if(y(k)){if("-"===e)e=k.length;else{if(c&&!l(e))throw new z("Expected an unsigned base-10 integer value, making the new referenced value the array element with the zero-based index","OPERATION_PATH_ILLEGAL_ARRAY_INDEX",g-1,d.path,d);e=parseInt(e,10)}if(m>=n){if(c&&"add"===d.op&&e>k.length)throw new z("The specified index MUST NOT be greater than the number of elements in the array","OPERATION_VALUE_OUT_OF_BOUNDS",g-1,d.path,d);f=t[d.op].call(d,k,e,a);break}}else if(e&&-1!=e.indexOf("~")&&(e=e.replace(/~1/g,"/").replace(/~0/g,"~")),m>=n){f=s[d.op].call(d,k,e,a);break}k=k[e]}}return f}function n(a,b){var c=[];return k(a,b,c,""),c}function o(a){if(void 0===a)return!0;if("array"==typeof a||"object"==typeof a)for(var b in a)if(o(a[b]))return!0;return!1}function p(b,c,d,e){if("object"!=typeof b||null===b||y(b))throw new z("Operation is not an object","OPERATION_NOT_AN_OBJECT",c,b,d);if(!s[b.op])throw new z("Operation `op` property is not one of operations defined in RFC-6902","OPERATION_OP_INVALID",c,b,d);if("string"!=typeof b.path)throw new z("Operation `path` property is not a string","OPERATION_PATH_INVALID",c,b,d);if(("move"===b.op||"copy"===b.op)&&"string"!=typeof b.from)throw new z("Operation `from` property is not present (applicable in `move` and `copy` operations)","OPERATION_FROM_REQUIRED",c,b,d);if(("add"===b.op||"replace"===b.op||"test"===b.op)&&void 0===b.value)throw new z("Operation `value` property is not present (applicable in `add`, `replace` and `test` operations)","OPERATION_VALUE_REQUIRED",c,b,d);if(("add"===b.op||"replace"===b.op||"test"===b.op)&&o(b.value))throw new z("Operation `value` property is not present (applicable in `add`, `replace` and `test` operations)","OPERATION_VALUE_CANNOT_CONTAIN_UNDEFINED",c,b,d);if(d)if("add"==b.op){var f=b.path.split("/").length,g=e.split("/").length;if(f!==g+1&&f!==g)throw new z("Cannot perform an `add` operation at the desired path","OPERATION_PATH_CANNOT_ADD",c,b,d)}else if("replace"===b.op||"remove"===b.op||"_get"===b.op){if(b.path!==e)throw new z("Cannot perform the operation at a path that does not exist","OPERATION_PATH_UNRESOLVABLE",c,b,d)}else if("move"===b.op||"copy"===b.op){var h={op:"_get",path:b.from,value:void 0},i=a.validate([h],d);if(i&&"OPERATION_PATH_UNRESOLVABLE"===i.name)throw new z("Cannot perform the operation from a path that does not exist","OPERATION_FROM_UNRESOLVABLE",c,b,d)}}function q(a,b){try{if(!y(a))throw new z("Patch sequence must be an array","SEQUENCE_NOT_AN_ARRAY");if(b)b=JSON.parse(JSON.stringify(b)),m.call(this,b,a,!0);else for(var c=0;c<a.length;c++)this.validator(a[c],c)}catch(d){if(d instanceof z)return d;throw d}}if(!a.observe){var r=function(a){if(y(a)){for(var b=new Array(a.length),c=0;c<b.length;c++)b[c]=c.toString();return b}if(Object.keys)return Object.keys(a);var b=[];for(var c in a)a.hasOwnProperty(c)&&b.push(c);return b},s={add:function(a,b){return a[b]=this.value,!0},remove:function(a,b){return delete a[b],!0},replace:function(a,b){return a[b]=this.value,!0},move:function(a,b,c){var d={op:"_get",path:this.from};return m(c,[d]),m(c,[{op:"remove",path:this.from}]),m(c,[{op:"add",path:this.path,value:d.value}]),!0},copy:function(a,b,c){var d={op:"_get",path:this.from};return m(c,[d]),m(c,[{op:"add",path:this.path,value:d.value}]),!0},test:function(a,c){return b(a[c],this.value)},_get:function(a,b){this.value=a[b]}},t={add:function(a,b){return a.splice(b,0,this.value),!0},remove:function(a,b){return a.splice(b,1),!0},replace:function(a,b){return a[b]=this.value,!0},move:s.move,copy:s.copy,test:s.test,_get:s._get},u={add:function(a){u.remove.call(this,a);for(var b in this.value)this.value.hasOwnProperty(b)&&(a[b]=this.value[b]);return!0},remove:function(a){for(var b in a)a.hasOwnProperty(b)&&s.remove.call(this,a,b);return!0},replace:function(a){return m(a,[{op:"remove",path:this.path}]),m(a,[{op:"add",path:this.path,value:this.value}]),!0},move:s.move,copy:s.copy,test:function(a){return JSON.stringify(a)===JSON.stringify(this.value)},_get:function(a){this.value=a}},v=[],w=function(){function a(a){this.observers=[],this.obj=a}return a}(),x=function(){function a(a,b){this.callback=a,this.observer=b}return a}();a.unobserve=g,a.observe=i,a.generate=j;var y;y=Array.isArray?Array.isArray:function(a){return a.push&&"number"==typeof a.length},a.apply=m,a.compare=n;var z=function(a){function b(b,c,d,e,f){a.call(this,b),this.message=b,this.name=c,this.index=d,this.operation=e,this.tree=f}return __extends(b,a),b}(OriginalError);a.JsonPatchError=z,a.Error=z,a.hasUndefined=o,a.validator=p,a.validate=q}}(jsonpatch||(jsonpatch={})),"undefined"!=typeof exports&&(exports.apply=jsonpatch.apply,exports.observe=jsonpatch.observe,exports.unobserve=jsonpatch.unobserve,exports.generate=jsonpatch.generate,exports.compare=jsonpatch.compare,exports.validate=jsonpatch.validate,exports.validator=jsonpatch.validator,exports.JsonPatchError=jsonpatch.JsonPatchError,exports.Error=jsonpatch.Error);
\ No newline at end of file
diff --git a/src/json-patch-duplex.js b/src/json-patch-duplex.js
index 970cdc5a..de31fb52 100644
--- a/src/json-patch-duplex.js
+++ b/src/json-patch-duplex.js
@@ -1,38 +1,36 @@
 /*!
-* https://github.com/Starcounter-Jack/JSON-Patch
-* json-patch-duplex.js version: 0.5.5
-* (c) 2013 Joachim Wester
-* MIT license
-*/
-var __extends = this.__extends || function (d, b) {
+ * https://github.com/Starcounter-Jack/JSON-Patch
+ * json-patch-duplex.js version: 0.5.5
+ * (c) 2013 Joachim Wester
+ * MIT license
+ */
+var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
-
 var OriginalError = Error;
-
 var jsonpatch;
 (function (jsonpatch) {
     /* Do nothing if module is already defined.
-    Doesn't look nice, as we cannot simply put
-    `!jsonpatch &&` before this immediate function call
-    in TypeScript.
-    */
+       Doesn't look nice, as we cannot simply put
+       `!jsonpatch &&` before this immediate function call
+       in TypeScript.
+       */
     if (jsonpatch.observe) {
         return;
     }
-
     var _objectKeys = function (obj) {
         if (_isArray(obj)) {
-            return Array.apply(null, { length: obj.length }).map(function (e, i, a) { return i.toString(); });
+            var keys = new Array(obj.length);
+            for (var i = 0; i < keys.length; i++) {
+                keys[i] = i.toString();
+            }
+            return keys;
         }
-
         if (Object.keys) {
             return Object.keys(obj);
         }
-
         var keys = [];
         for (var i in obj) {
             if (obj.hasOwnProperty(i)) {
@@ -41,10 +39,9 @@ var jsonpatch;
         }
         return keys;
     };
-
     function _equals(a, b) {
         switch (typeof a) {
-            case 'undefined':
+            case 'undefined': //backward compatibility, but really I think we should return false
             case 'boolean':
             case 'string':
             case 'number':
@@ -55,36 +52,29 @@ var jsonpatch;
                 if (_isArray(a)) {
                     if (!_isArray(b) || a.length !== b.length)
                         return false;
-
                     for (var i = 0, l = a.length; i < l; i++)
                         if (!_equals(a[i], b[i]))
                             return false;
-
                     return true;
                 }
-
                 var bKeys = _objectKeys(b);
                 var bLength = bKeys.length;
                 if (_objectKeys(a).length !== bLength)
                     return false;
-
                 for (var i = 0; i < bLength; i++)
                     if (!_equals(a[i], b[i]))
                         return false;
-
                 return true;
-
             default:
                 return false;
         }
     }
-
     /* We use a Javascript hash to store each
-    function. Each hash entry (property) uses
-    the operation identifiers specified in rfc6902.
-    In this way, we can map each patch operation
-    to its dedicated function in efficient way.
-    */
+     function. Each hash entry (property) uses
+     the operation identifiers specified in rfc6902.
+     In this way, we can map each patch operation
+     to its dedicated function in efficient way.
+     */
     /* The operations applicable to an object */
     var objOps = {
         add: function (obj, key) {
@@ -125,7 +115,6 @@ var jsonpatch;
             this.value = obj[key];
         }
     };
-
     /* The operations applicable to an array. Many are the same as for the object */
     var arrOps = {
         add: function (arr, i) {
@@ -145,7 +134,6 @@ var jsonpatch;
         test: objOps.test,
         _get: objOps._get
     };
-
     /* The operations applicable to object root. Many are the same as for the object */
     var rootOps = {
         add: function (obj) {
@@ -183,13 +171,13 @@ var jsonpatch;
             this.value = obj;
         }
     };
-
     var observeOps = {
         add: function (patches, path) {
             var patch = {
                 op: "add",
                 path: path + escapePathComponent(this.name),
-                value: this.object[this.name] };
+                value: this.object[this.name]
+            };
             patches.push(patch);
         },
         'delete': function (patches, path) {
@@ -208,20 +196,19 @@ var jsonpatch;
             patches.push(patch);
         }
     };
-
     function escapePathComponent(str) {
         if (str.indexOf('/') === -1 && str.indexOf('~') === -1)
             return str;
         return str.replace(/~/g, '~0').replace(/\//g, '~1');
     }
-
     function _getPathRecursive(root, obj) {
         var found;
         for (var key in root) {
             if (root.hasOwnProperty(key)) {
                 if (root[key] === obj) {
                     return escapePathComponent(key) + '/';
-                } else if (typeof root[key] === 'object') {
+                }
+                else if (typeof root[key] === 'object') {
                     found = _getPathRecursive(root[key], obj);
                     if (found != '') {
                         return escapePathComponent(key) + '/' + found;
@@ -231,7 +218,6 @@ var jsonpatch;
         }
         return '';
     }
-
     function getPath(root, obj) {
         if (root === obj) {
             return '/';
@@ -242,11 +228,7 @@ var jsonpatch;
         }
         return '/' + path;
     }
-
     var beforeDict = [];
-
-    jsonpatch.intervals;
-
     var Mirror = (function () {
         function Mirror(obj) {
             this.observers = [];
@@ -254,7 +236,6 @@ var jsonpatch;
         }
         return Mirror;
     })();
-
     var ObserverInfo = (function () {
         function ObserverInfo(callback, observer) {
             this.callback = callback;
@@ -262,7 +243,6 @@ var jsonpatch;
         }
         return ObserverInfo;
     })();
-
     function getMirror(obj) {
         for (var i = 0, ilen = beforeDict.length; i < ilen; i++) {
             if (beforeDict[i].obj === obj) {
@@ -270,7 +250,6 @@ var jsonpatch;
             }
         }
     }
-
     function getObserverFromMirror(mirror, callback) {
         for (var j = 0, jlen = mirror.observers.length; j < jlen; j++) {
             if (mirror.observers[j].callback === callback) {
@@ -278,7 +257,6 @@ var jsonpatch;
             }
         }
     }
-
     function removeObserverFromMirror(mirror, observer) {
         for (var j = 0, jlen = mirror.observers.length; j < jlen; j++) {
             if (mirror.observers[j].observer === observer) {
@@ -287,95 +265,84 @@ var jsonpatch;
             }
         }
     }
-
     function unobserve(root, observer) {
         generate(observer);
         clearTimeout(observer.next);
-
         var mirror = getMirror(root);
         removeObserverFromMirror(mirror, observer);
     }
     jsonpatch.unobserve = unobserve;
-
     function deepClone(obj) {
         if (typeof obj === "object") {
-            return JSON.parse(JSON.stringify(obj));
-        } else {
-            return obj;
+            return JSON.parse(JSON.stringify(obj)); //Faster than ES5 clone - http://jsperf.com/deep-cloning-of-objects/5
+        }
+        else {
+            return obj; //no need to clone primitives
         }
     }
-
     function observe(obj, callback) {
         var patches = [];
         var root = obj;
         var observer;
         var mirror = getMirror(obj);
-
         if (!mirror) {
             mirror = new Mirror(obj);
             beforeDict.push(mirror);
-        } else {
+        }
+        else {
             observer = getObserverFromMirror(mirror, callback);
         }
-
         if (observer) {
             return observer;
         }
-
         observer = {};
-
         mirror.value = deepClone(obj);
-
         if (callback) {
-                //callbacks.push(callback); this has no purpose
-                observer.callback = callback;
-                observer.next = null;
-                var intervals = this.intervals || [100, 1000, 10000, 60000];
-                if (intervals.push === void 0) {
-                    throw new OriginalError("jsonpatch.intervals must be an array");
-                }
-                var currentInterval = 0;
-
-                var dirtyCheck = function () {
-                    generate(observer);
-                };
-                var fastCheck = function () {
-                    clearTimeout(observer.next);
-                    observer.next = setTimeout(function () {
-                        dirtyCheck();
-                        currentInterval = 0;
-                        observer.next = setTimeout(slowCheck, intervals[currentInterval++]);
-                    }, 0);
-                };
-                var slowCheck = function () {
+            //callbacks.push(callback); this has no purpose
+            observer.callback = callback;
+            observer.next = null;
+            var intervals = this.intervals || [100, 1000, 10000, 60000];
+            if (intervals.push === void 0) {
+                throw new OriginalError("jsonpatch.intervals must be an array");
+            }
+            var currentInterval = 0;
+            var dirtyCheck = function () {
+                generate(observer);
+            };
+            var fastCheck = function () {
+                clearTimeout(observer.next);
+                observer.next = setTimeout(function () {
                     dirtyCheck();
-                    if (currentInterval == intervals.length)
-                        currentInterval = intervals.length - 1;
+                    currentInterval = 0;
                     observer.next = setTimeout(slowCheck, intervals[currentInterval++]);
-                };
-                if (typeof window !== 'undefined') {
-                    if (window.addEventListener) {
-                        window.addEventListener('mousedown', fastCheck);
-                        window.addEventListener('mouseup', fastCheck);
-                        window.addEventListener('keydown', fastCheck);
-                    } else {
-                        document.documentElement.attachEvent('onmousedown', fastCheck);
-                        document.documentElement.attachEvent('onmouseup', fastCheck);
-                        document.documentElement.attachEvent('onkeydown', fastCheck);
-                    }
-                }
+                }, 0);
+            };
+            var slowCheck = function () {
+                dirtyCheck();
+                if (currentInterval == intervals.length)
+                    currentInterval = intervals.length - 1;
                 observer.next = setTimeout(slowCheck, intervals[currentInterval++]);
+            };
+            if (typeof window !== 'undefined') {
+                if (window.addEventListener) {
+                    window.addEventListener('mousedown', fastCheck);
+                    window.addEventListener('mouseup', fastCheck);
+                    window.addEventListener('keydown', fastCheck);
+                }
+                else {
+                    document.documentElement.attachEvent('onmousedown', fastCheck);
+                    document.documentElement.attachEvent('onmouseup', fastCheck);
+                    document.documentElement.attachEvent('onkeydown', fastCheck);
+                }
+            }
+            observer.next = setTimeout(slowCheck, intervals[currentInterval++]);
         }
-
         observer.patches = patches;
         observer.object = obj;
-
         mirror.observers.push(new ObserverInfo(callback, observer));
-
         return observer;
     }
     jsonpatch.observe = observe;
-
     function generate(observer) {
         var mirror;
         for (var i = 0, ilen = beforeDict.length; i < ilen; i++) {
@@ -388,7 +355,6 @@ var jsonpatch;
         if (observer.patches.length) {
             apply(mirror.value, observer.patches);
         }
-
         var temp = observer.patches;
         if (temp.length > 0) {
             observer.patches = [];
@@ -399,14 +365,13 @@ var jsonpatch;
         return temp;
     }
     jsonpatch.generate = generate;
-
     // Dirty check if obj is different from mirror, generate patches and update mirror
     function _generate(mirror, obj, patches, path) {
         var newKeys = _objectKeys(obj);
         var oldKeys = _objectKeys(mirror);
         var changed = false;
         var deleted = false;
-
+        //if ever "move" operation is implemented here, make sure this test runs OK: "should not generate the same patch twice (move)"
         for (var t = oldKeys.length - 1; t >= 0; t--) {
             var key = oldKeys[t];
             var oldVal = mirror[key];
@@ -414,22 +379,22 @@ var jsonpatch;
                 var newVal = obj[key];
                 if (typeof oldVal == "object" && oldVal != null && typeof newVal == "object" && newVal != null) {
                     _generate(oldVal, newVal, patches, path + "/" + escapePathComponent(key));
-                } else {
+                }
+                else {
                     if (oldVal != newVal) {
                         changed = true;
                         patches.push({ op: "replace", path: path + "/" + escapePathComponent(key), value: deepClone(newVal) });
                     }
                 }
-            } else {
+            }
+            else {
                 patches.push({ op: "remove", path: path + "/" + escapePathComponent(key) });
                 deleted = true; // property has been deleted
             }
         }
-
         if (!deleted && newKeys.length == oldKeys.length) {
             return;
         }
-
         for (var t = 0; t < newKeys.length; t++) {
             var key = newKeys[t];
             if (!mirror.hasOwnProperty(key)) {
@@ -437,16 +402,15 @@ var jsonpatch;
             }
         }
     }
-
     var _isArray;
     if (Array.isArray) {
         _isArray = Array.isArray;
-    } else {
+    }
+    else {
         _isArray = function (obj) {
             return obj.push && typeof obj.length === 'number';
         };
     }
-
     //3x faster than cached /^\d+$/.test(str)
     function isInteger(str) {
         var i = 0;
@@ -462,30 +426,27 @@ var jsonpatch;
         }
         return true;
     }
-
     /// Apply a json-patch operation on an object tree
     function apply(tree, patches, validate) {
         var result = false, p = 0, plen = patches.length, patch, key;
         while (p < plen) {
             patch = patches[p];
             p++;
-
             // Find the object
             var path = patch.path || "";
             var keys = path.split('/');
             var obj = tree;
-            var t = 1;
+            var t = 1; //skip empty element - http://jsperf.com/to-shift-or-not-to-shift
             var len = keys.length;
             var existingPathFragment = undefined;
-
             while (true) {
                 key = keys[t];
-
                 if (validate) {
                     if (existingPathFragment === undefined) {
                         if (obj[key] === undefined) {
                             existingPathFragment = keys.slice(0, t).join('/');
-                        } else if (t == len - 1) {
+                        }
+                        else if (t == len - 1) {
                             existingPathFragment = patch.path;
                         }
                         if (existingPathFragment !== undefined) {
@@ -493,7 +454,6 @@ var jsonpatch;
                         }
                     }
                 }
-
                 t++;
                 if (key === undefined) {
                     if (t >= len) {
@@ -504,7 +464,8 @@ var jsonpatch;
                 if (_isArray(obj)) {
                     if (key === '-') {
                         key = obj.length;
-                    } else {
+                    }
+                    else {
                         if (validate && !isInteger(key)) {
                             throw new JsonPatchError("Expected an unsigned base-10 integer value, making the new referenced value the array element with the zero-based index", "OPERATION_PATH_ILLEGAL_ARRAY_INDEX", p - 1, patch.path, patch);
                         }
@@ -517,7 +478,8 @@ var jsonpatch;
                         result = arrOps[patch.op].call(patch, obj, key, tree); // Apply patch
                         break;
                     }
-                } else {
+                }
+                else {
                     if (key && key.indexOf('~') != -1)
                         key = key.replace(/~1/g, '/').replace(/~0/g, '~'); // escape chars
                     if (t >= len) {
@@ -531,14 +493,12 @@ var jsonpatch;
         return result;
     }
     jsonpatch.apply = apply;
-
     function compare(tree1, tree2) {
         var patches = [];
         _generate(tree1, tree2, patches, '');
         return patches;
     }
     jsonpatch.compare = compare;
-
     var JsonPatchError = (function (_super) {
         __extends(JsonPatchError, _super);
         function JsonPatchError(message, name, index, operation, tree) {
@@ -552,17 +512,14 @@ var jsonpatch;
         return JsonPatchError;
     })(OriginalError);
     jsonpatch.JsonPatchError = JsonPatchError;
-
     jsonpatch.Error = JsonPatchError;
-
     /**
-    * Recursively checks whether an object has any undefined values inside.
-    */
+     * Recursively checks whether an object has any undefined values inside.
+     */
     function hasUndefined(obj) {
         if (obj === undefined) {
             return true;
         }
-
         if (typeof obj == "array" || typeof obj == "object") {
             for (var i in obj) {
                 if (hasUndefined(obj[i])) {
@@ -570,42 +527,49 @@ var jsonpatch;
                 }
             }
         }
-
         return false;
     }
-
+    jsonpatch.hasUndefined = hasUndefined;
     /**
-    * Validates a single operation. Called from `jsonpatch.validate`. Throws `JsonPatchError` in case of an error.
-    * @param {object} operation - operation object (patch)
-    * @param {number} index - index of operation in the sequence
-    * @param {object} [tree] - object where the operation is supposed to be applied
-    * @param {string} [existingPathFragment] - comes along with `tree`
-    */
+     * Validates a single operation. Called from `jsonpatch.validate`. Throws `JsonPatchError` in case of an error.
+     * @param {object} operation - operation object (patch)
+     * @param {number} index - index of operation in the sequence
+     * @param {object} [tree] - object where the operation is supposed to be applied
+     * @param {string} [existingPathFragment] - comes along with `tree`
+     */
     function validator(operation, index, tree, existingPathFragment) {
         if (typeof operation !== 'object' || operation === null || _isArray(operation)) {
             throw new JsonPatchError('Operation is not an object', 'OPERATION_NOT_AN_OBJECT', index, operation, tree);
-        } else if (!objOps[operation.op]) {
+        }
+        else if (!objOps[operation.op]) {
             throw new JsonPatchError('Operation `op` property is not one of operations defined in RFC-6902', 'OPERATION_OP_INVALID', index, operation, tree);
-        } else if (typeof operation.path !== 'string') {
+        }
+        else if (typeof operation.path !== 'string') {
             throw new JsonPatchError('Operation `path` property is not a string', 'OPERATION_PATH_INVALID', index, operation, tree);
-        } else if ((operation.op === 'move' || operation.op === 'copy') && typeof operation.from !== 'string') {
+        }
+        else if ((operation.op === 'move' || operation.op === 'copy') && typeof operation.from !== 'string') {
             throw new JsonPatchError('Operation `from` property is not present (applicable in `move` and `copy` operations)', 'OPERATION_FROM_REQUIRED', index, operation, tree);
-        } else if ((operation.op === 'add' || operation.op === 'replace' || operation.op === 'test') && operation.value === undefined) {
+        }
+        else if ((operation.op === 'add' || operation.op === 'replace' || operation.op === 'test') && operation.value === undefined) {
             throw new JsonPatchError('Operation `value` property is not present (applicable in `add`, `replace` and `test` operations)', 'OPERATION_VALUE_REQUIRED', index, operation, tree);
-        } else if ((operation.op === 'add' || operation.op === 'replace' || operation.op === 'test') && hasUndefined(operation.value)) {
+        }
+        else if ((operation.op === 'add' || operation.op === 'replace' || operation.op === 'test') && hasUndefined(operation.value)) {
             throw new JsonPatchError('Operation `value` property is not present (applicable in `add`, `replace` and `test` operations)', 'OPERATION_VALUE_CANNOT_CONTAIN_UNDEFINED', index, operation, tree);
-        } else if (tree) {
+        }
+        else if (tree) {
             if (operation.op == "add") {
                 var pathLen = operation.path.split("/").length;
                 var existingPathLen = existingPathFragment.split("/").length;
                 if (pathLen !== existingPathLen + 1 && pathLen !== existingPathLen) {
                     throw new JsonPatchError('Cannot perform an `add` operation at the desired path', 'OPERATION_PATH_CANNOT_ADD', index, operation, tree);
                 }
-            } else if (operation.op === 'replace' || operation.op === 'remove' || operation.op === '_get') {
+            }
+            else if (operation.op === 'replace' || operation.op === 'remove' || operation.op === '_get') {
                 if (operation.path !== existingPathFragment) {
                     throw new JsonPatchError('Cannot perform the operation at a path that does not exist', 'OPERATION_PATH_UNRESOLVABLE', index, operation, tree);
                 }
-            } else if (operation.op === 'move' || operation.op === 'copy') {
+            }
+            else if (operation.op === 'move' || operation.op === 'copy') {
                 var existingValue = { op: "_get", path: operation.from, value: undefined };
                 var error = jsonpatch.validate([existingValue], tree);
                 if (error && error.name === 'OPERATION_PATH_UNRESOLVABLE') {
@@ -615,39 +579,39 @@ var jsonpatch;
         }
     }
     jsonpatch.validator = validator;
-
     /**
-    * Validates a sequence of operations. If `tree` parameter is provided, the sequence is additionally validated against the object tree.
-    * If error is encountered, returns a JsonPatchError object
-    * @param sequence
-    * @param tree
-    * @returns {JsonPatchError|undefined}
-    */
+     * Validates a sequence of operations. If `tree` parameter is provided, the sequence is additionally validated against the object tree.
+     * If error is encountered, returns a JsonPatchError object
+     * @param sequence
+     * @param tree
+     * @returns {JsonPatchError|undefined}
+     */
     function validate(sequence, tree) {
-        try  {
+        try {
             if (!_isArray(sequence)) {
                 throw new JsonPatchError('Patch sequence must be an array', 'SEQUENCE_NOT_AN_ARRAY');
             }
-
             if (tree) {
                 tree = JSON.parse(JSON.stringify(tree)); //clone tree so that we can safely try applying operations
                 apply.call(this, tree, sequence, true);
-            } else {
+            }
+            else {
                 for (var i = 0; i < sequence.length; i++) {
                     this.validator(sequence[i], i);
                 }
             }
-        } catch (e) {
+        }
+        catch (e) {
             if (e instanceof JsonPatchError) {
                 return e;
-            } else {
+            }
+            else {
                 throw e;
             }
         }
     }
     jsonpatch.validate = validate;
 })(jsonpatch || (jsonpatch = {}));
-
 if (typeof exports !== "undefined") {
     exports.apply = jsonpatch.apply;
     exports.observe = jsonpatch.observe;