// IE 11 CustomEvent polyfill

(function () {
  if ( typeof window.CustomEvent === "function" ) return false; //If not IE

  function CustomEvent ( event, params ) {
    params = params || { bubbles: false, cancelable: false, detail: undefined };
    var evt = document.createEvent( 'CustomEvent' );
    evt.initCustomEvent( event, params.bubbles, params.cancelable, params.detail );
    return evt;
   }

  CustomEvent.prototype = window.Event.prototype;

  window.CustomEvent = CustomEvent;
})();

// IE 11 EventTarget polyfill
(function () {
  if (typeof window.EventTarget === "function") return false; // If EventTarget exists

  function EventTarget() {
    this._listeners = {};
  }

  EventTarget.prototype.addEventListener = function(type, callback) {
    if (!(type in this._listeners)) {
      this._listeners[type] = [];
    }
    this._listeners[type].push(callback);
  };

  EventTarget.prototype.removeEventListener = function(type, callback) {
    if (!(type in this._listeners)) {
      return;
    }
    var stack = this._listeners[type];
    for (var i = 0, l = stack.length; i < l; i++) {
      if (stack[i] === callback) {
        stack.splice(i, 1);
        return;
      }
    }
  };

  EventTarget.prototype.dispatchEvent = function(event) {
    if (!(event.type in this._listeners)) {
      return true;
    }
    var stack = this._listeners[event.type].slice();

    for (var i = 0, l = stack.length; i < l; i++) {
      stack[i].call(this, event);
    }
    return !event.defaultPrevented;
  };

  window.EventTarget = EventTarget;
})();

// IE 11 Array.isArray polyfill (just in case)
if (!Array.isArray) {
  Array.isArray = function(arg) {
    return Object.prototype.toString.call(arg) === '[object Array]';
  };
}


/*! Native Promise Only
    v0.8.1 (c) Kyle Simpson
    MIT License: http://getify.mit-license.org
*/

(function UMD(name,context,definition){
	// special form of UMD for polyfilling across environments
	context[name] = context[name] || definition();
	if (typeof module != "undefined" && module.exports) { module.exports = context[name]; }
	else if (typeof define == "function" && define.amd) { define(function $AMD$(){ return context[name]; }); }
})("Promise",typeof global != "undefined" ? global : this,function DEF(){
	/*jshint validthis:true */
	"use strict";

	var builtInProp, cycle, scheduling_queue,
		ToString = Object.prototype.toString,
		timer = (typeof setImmediate != "undefined") ?
			function timer(fn) { return setImmediate(fn); } :
			setTimeout
	;

	// dammit, IE8.
	try {
		Object.defineProperty({},"x",{});
		builtInProp = function builtInProp(obj,name,val,config) {
			return Object.defineProperty(obj,name,{
				value: val,
				writable: true,
				configurable: config !== false
			});
		};
	}
	catch (err) {
		builtInProp = function builtInProp(obj,name,val) {
			obj[name] = val;
			return obj;
		};
	}

	// Note: using a queue instead of array for efficiency
	scheduling_queue = (function Queue() {
		var first, last, item;

		function Item(fn,self) {
			this.fn = fn;
			this.self = self;
			this.next = void 0;
		}

		return {
			add: function add(fn,self) {
				item = new Item(fn,self);
				if (last) {
					last.next = item;
				}
				else {
					first = item;
				}
				last = item;
				item = void 0;
			},
			drain: function drain() {
				var f = first;
				first = last = cycle = void 0;

				while (f) {
					f.fn.call(f.self);
					f = f.next;
				}
			}
		};
	})();

	function schedule(fn,self) {
		scheduling_queue.add(fn,self);
		if (!cycle) {
			cycle = timer(scheduling_queue.drain);
		}
	}

	// promise duck typing
	function isThenable(o) {
		var _then, o_type = typeof o;

		if (o != null &&
			(
				o_type == "object" || o_type == "function"
			)
		) {
			_then = o.then;
		}
		return typeof _then == "function" ? _then : false;
	}

	function notify() {
		for (var i=0; i<this.chain.length; i++) {
			notifyIsolated(
				this,
				(this.state === 1) ? this.chain[i].success : this.chain[i].failure,
				this.chain[i]
			);
		}
		this.chain.length = 0;
	}

	// NOTE: This is a separate function to isolate
	// the `try..catch` so that other code can be
	// optimized better
	function notifyIsolated(self,cb,chain) {
		var ret, _then;
		try {
			if (cb === false) {
				chain.reject(self.msg);
			}
			else {
				if (cb === true) {
					ret = self.msg;
				}
				else {
					ret = cb.call(void 0,self.msg);
				}

				if (ret === chain.promise) {
					chain.reject(TypeError("Promise-chain cycle"));
				}
				else if (_then = isThenable(ret)) {
					_then.call(ret,chain.resolve,chain.reject);
				}
				else {
					chain.resolve(ret);
				}
			}
		}
		catch (err) {
			chain.reject(err);
		}
	}

	function resolve(msg) {
		var _then, self = this;

		// already triggered?
		if (self.triggered) { return; }

		self.triggered = true;

		// unwrap
		if (self.def) {
			self = self.def;
		}

		try {
			if (_then = isThenable(msg)) {
				schedule(function(){
					var def_wrapper = new MakeDefWrapper(self);
					try {
						_then.call(msg,
							function $resolve$(){ resolve.apply(def_wrapper,arguments); },
							function $reject$(){ reject.apply(def_wrapper,arguments); }
						);
					}
					catch (err) {
						reject.call(def_wrapper,err);
					}
				})
			}
			else {
				self.msg = msg;
				self.state = 1;
				if (self.chain.length > 0) {
					schedule(notify,self);
				}
			}
		}
		catch (err) {
			reject.call(new MakeDefWrapper(self),err);
		}
	}

	function reject(msg) {
		var self = this;

		// already triggered?
		if (self.triggered) { return; }

		self.triggered = true;

		// unwrap
		if (self.def) {
			self = self.def;
		}

		self.msg = msg;
		self.state = 2;
		if (self.chain.length > 0) {
			schedule(notify,self);
		}
	}

	function iteratePromises(Constructor,arr,resolver,rejecter) {
		for (var idx=0; idx<arr.length; idx++) {
			(function IIFE(idx){
				Constructor.resolve(arr[idx])
				.then(
					function $resolver$(msg){
						resolver(idx,msg);
					},
					rejecter
				);
			})(idx);
		}
	}

	function MakeDefWrapper(self) {
		this.def = self;
		this.triggered = false;
	}

	function MakeDef(self) {
		this.promise = self;
		this.state = 0;
		this.triggered = false;
		this.chain = [];
		this.msg = void 0;
	}

	function Promise(executor) {
		if (typeof executor != "function") {
			throw TypeError("Not a function");
		}

		if (this.__NPO__ !== 0) {
			throw TypeError("Not a promise");
		}

		// instance shadowing the inherited "brand"
		// to signal an already "initialized" promise
		this.__NPO__ = 1;

		var def = new MakeDef(this);

		this["then"] = function then(success,failure) {
			var o = {
				success: typeof success == "function" ? success : true,
				failure: typeof failure == "function" ? failure : false
			};
			// Note: `then(..)` itself can be borrowed to be used against
			// a different promise constructor for making the chained promise,
			// by substituting a different `this` binding.
			o.promise = new this.constructor(function extractChain(resolve,reject) {
				if (typeof resolve != "function" || typeof reject != "function") {
					throw TypeError("Not a function");
				}

				o.resolve = resolve;
				o.reject = reject;
			});
			def.chain.push(o);

			if (def.state !== 0) {
				schedule(notify,def);
			}

			return o.promise;
		};
		this["catch"] = function $catch$(failure) {
			return this.then(void 0,failure);
		};

		try {
			executor.call(
				void 0,
				function publicResolve(msg){
					resolve.call(def,msg);
				},
				function publicReject(msg) {
					reject.call(def,msg);
				}
			);
		}
		catch (err) {
			reject.call(def,err);
		}
	}

	var PromisePrototype = builtInProp({},"constructor",Promise,
		/*configurable=*/false
	);

	// Note: Android 4 cannot use `Object.defineProperty(..)` here
	Promise.prototype = PromisePrototype;

	// built-in "brand" to signal an "uninitialized" promise
	builtInProp(PromisePrototype,"__NPO__",0,
		/*configurable=*/false
	);

	builtInProp(Promise,"resolve",function Promise$resolve(msg) {
		var Constructor = this;

		// spec mandated checks
		// note: best "isPromise" check that's practical for now
		if (msg && typeof msg == "object" && msg.__NPO__ === 1) {
			return msg;
		}

		return new Constructor(function executor(resolve,reject){
			if (typeof resolve != "function" || typeof reject != "function") {
				throw TypeError("Not a function");
			}

			resolve(msg);
		});
	});

	builtInProp(Promise,"reject",function Promise$reject(msg) {
		return new this(function executor(resolve,reject){
			if (typeof resolve != "function" || typeof reject != "function") {
				throw TypeError("Not a function");
			}

			reject(msg);
		});
	});

	builtInProp(Promise,"all",function Promise$all(arr) {
		var Constructor = this;

		// spec mandated checks
		if (ToString.call(arr) != "[object Array]") {
			return Constructor.reject(TypeError("Not an array"));
		}
		if (arr.length === 0) {
			return Constructor.resolve([]);
		}

		return new Constructor(function executor(resolve,reject){
			if (typeof resolve != "function" || typeof reject != "function") {
				throw TypeError("Not a function");
			}

			var len = arr.length, msgs = Array(len), count = 0;

			iteratePromises(Constructor,arr,function resolver(idx,msg) {
				msgs[idx] = msg;
				if (++count === len) {
					resolve(msgs);
				}
			},reject);
		});
	});

	builtInProp(Promise,"race",function Promise$race(arr) {
		var Constructor = this;

		// spec mandated checks
		if (ToString.call(arr) != "[object Array]") {
			return Constructor.reject(TypeError("Not an array"));
		}

		return new Constructor(function executor(resolve,reject){
			if (typeof resolve != "function" || typeof reject != "function") {
				throw TypeError("Not a function");
			}

			iteratePromises(Constructor,arr,function resolver(idx,msg){
				resolve(msg);
			},reject);
		});
	});

	return Promise;
});


/*!
 * Symbol-ES6 v0.1.2
 * ES6 Symbol polyfill in pure ES5.
 *
 * @license Copyright (c) 2017-2018 Rousan Ali, MIT License
 *
 * Codebase: https://github.com/rousan/symbol-es6
 * Date: 28th Jan, 2018
 */

(function (global, factory) {

	"use strict";

	if (typeof module === "object" && typeof module.exports === "object") {
			// For the environment like NodeJS, CommonJS etc where module or
			// module.exports objects are available
			module.exports = factory(global);
	} else {
			// For browser context, where global object is window
			factory(global);
	}

	/* window is for browser environment and global is for NodeJS environment */
})(typeof window !== "undefined" ? window : global, function (global) {

	"use strict";

	var defineProperty = Object.defineProperty;

	var defineProperties = Object.defineProperties;

	var symbolHiddenCounter = 0;

	var globalSymbolRegistry = [];

	var slice = Array.prototype.slice;

	var ES6 = typeof global.ES6 === "object" ? global.ES6 : (global.ES6 = {});

	var isArray = Array.isArray;

	var objectToString = Object.prototype.toString;

	var push = Array.prototype.push;

	var emptyFunction = function () {};

	var simpleFunction = function (arg) {
			return arg;
	};

	var isCallable = function (fn) {
			return typeof fn === 'function';
	};

	var isConstructor = function (fn) {
			return isCallable(fn);
	};

	var Iterator = function () {};

	var ArrayIterator = function ArrayIterator(array, flag) {
			this._array = array;
			this._flag = flag;
			this._nextIndex = 0;
	};

	var StringIterator = function StringIterator(string, flag) {
			this._string = string;
			this._flag = flag;
			this._nextIndex = 0;
	};

	var isES6Running = function() {
			return false; /* Now 'false' for testing purpose */
	};

	var isObject = function (value) {
			return value !== null && (typeof value === "object" || typeof value === "function");
	};

	var es6FunctionPrototypeHasInstanceSymbol = function (instance) {
			if (typeof this !== "function")
					return false;
			return instance instanceof this;
	};

	var es6InstanceOfOperator = function (object, constructor) {
			if (!isObject(constructor))
					throw new TypeError("Right-hand side of 'instanceof' is not an object");

			var hasInstanceSymbolProp = constructor[Symbol.hasInstance];
			if (typeof hasInstanceSymbolProp === "undefined") {
					return object instanceof constructor;
			} else if(typeof hasInstanceSymbolProp !== "function") {
					throw new TypeError(typeof hasInstanceSymbolProp + " is not a function");
			} else {
					return hasInstanceSymbolProp.call(constructor, object);
			}
	};

	// Generates name for a symbol instance and this name will be used as
	// property key for property symbols internally.
	var generateSymbolName = function (id) {
			return "@@_____" + id + "_____";
	};

	// Generates id for next Symbol instance
	var getNextSymbolId = function () {
			return symbolHiddenCounter++;
	};

	var setupSymbolInternals = function (symbol, desc) {
			defineProperties(symbol, {
					_description: {
							value: desc
					},
					_isSymbol: {
							value: true
					},
					_id: {
							value: getNextSymbolId()
					}
			});
			return symbol;
	};

	var checkSymbolInternals = function (symbol) {
			return symbol._isSymbol === true && typeof symbol._id === "number" && typeof symbol._description === "string";
	};

	var isSymbol = function (symbol) {
			return symbol instanceof Symbol && checkSymbolInternals(symbol);
	};

	var symbolFor = function (key) {
			key = String(key);
			var registryLength = globalSymbolRegistry.length,
					record,
					i = 0;

			for(; i<registryLength; ++i) {
					record = globalSymbolRegistry[i];
					if (record.key === key)
							return record.symbol;
			}

			record = {
					key: key,
					symbol: Symbol(key)
			};
			globalSymbolRegistry.push(record);
			return record.symbol;
	};

	var symbolKeyFor = function (symbol) {
			if (!ES6.isSymbol(symbol))
					throw new TypeError(String(symbol) + " is not a symbol");
			var registryLength = globalSymbolRegistry.length,
					record,
					i = 0;

			for(; i<registryLength; ++i) {
					record = globalSymbolRegistry[i];
					if (record.symbol === symbol)
							return record.key;
			}
	};

	/* It affects array1 and appends array2 at the end of array1 */
	var appendArray = function (array1, array2) {
			// Returns immediately if these are not array or not array-like objects
			if (!(typeof array1.length === "number" && array1.length >= 0 && typeof array2.length === "number" && array2.length >= 0))
					return;
			var length1 = Math.floor(array1.length),
					length2 = Math.floor(array2.length),
					i = 0;

			array1.length = length1 + length2;
			for (; i<length2; ++i)
					if (array2.hasOwnProperty(i))
							array1[length1 + i] = array2[i];
	};

	var es6ObjectPrototypeToString = function toString() {
			if (this === undefined || this === null)
					return objectToString.call(this);
			// Add support for @@toStringTag symbol
			if (typeof this[Symbol.toStringTag] === "string")
					return "[object " + this[Symbol.toStringTag] + "]";
			else
					return objectToString.call(this);
	};

	var es6ArrayPrototypeConcat = function concat() {
			if (this === undefined || this === null)
					throw new TypeError("Array.prototype.concat called on null or undefined");

			// Boxing 'this' value to wrapper object
			var self = Object(this),
					targets = slice.call(arguments),
					outputs = []; // Later it may affected by Symbol

			targets.unshift(self);

			targets.forEach(function (target) {
					// If target is primitive then just push
					if (!isObject(target))
							outputs.push(target);
					// Here Symbol.isConcatSpreadable support is added
					else if (typeof target[Symbol.isConcatSpreadable] !== "undefined") {
							if (target[Symbol.isConcatSpreadable]) {
									appendArray(outputs, target);
							} else {
									outputs.push(target);
							}
					} else if (isArray(target)) {
							appendArray(outputs, target);
					} else {
							outputs.push(target);
					}
			});
			return outputs;
	};

	var es6ForOfLoop = function (iterable, callback, thisArg) {
			callback = typeof callback !== "function" ? emptyFunction : callback;
			if (typeof iterable[Symbol.iterator] !== "function")
					throw new TypeError("Iterable[Symbol.iterator] is not a function");
			var iterator = iterable[Symbol.iterator](),
					iterationResult;
			if (typeof iterator.next !== "function")
					throw new TypeError(".iterator.next is not a function");
			while (true) {
					iterationResult = iterator.next();
					if (!isObject(iterationResult))
							throw new TypeError("Iterator result " + iterationResult + " is not an object");
					if (iterationResult.done)
							break;
					callback.call(thisArg, iterationResult.value);
			}
	};

	// Provides simple inheritance functionality
	var simpleInheritance = function (child, parent) {
			if (typeof child !== "function" || typeof parent !== "function")
					throw new TypeError("Child and Parent must be function type");

			child.prototype = Object.create(parent.prototype);
			child.prototype.constructor = child;
	};

	// Behaves as Symbol function in ES6, take description and returns an unique object,
	// but in ES6 this function returns 'symbol' primitive typed value.
	// Its type is 'object' not 'symbol'.
	// There is no wrapping in this case i.e. Object(sym) = sym.
	var Symbol = function Symbol(desc) {
			desc = typeof desc === "undefined" ? "" : String(desc);

			if(this instanceof Symbol)
					throw new TypeError("Symbol is not a constructor");

			return setupSymbolInternals(Object.create(Symbol.prototype), desc);
	};

	defineProperties(Symbol, {

			"for": {
					value: symbolFor,
					writable: true,
					configurable: true
			},

			"keyFor": {
					value: symbolKeyFor,
					writable: true,
					configurable: true
			},

			"hasInstance": {
					value: Symbol("Symbol.hasInstance")
			},

			"isConcatSpreadable": {
					value: Symbol("Symbol.isConcatSpreadable")
			},

			"iterator": {
					value: Symbol("Symbol.iterator")
			},

			"toStringTag": {
					value: Symbol("Symbol.toStringTag")
			}
	});

	// In ES6, this function returns like 'Symbol(<desc>)', but in this case
	// this function returns the symbol's internal name to work properly.
	Symbol.prototype.toString = function () {
			return generateSymbolName(this._id);
	};

	// Returns itself but in ES6 It returns 'symbol' typed value.
	Symbol.prototype.valueOf = function () {
			return this;
	};

	// Make Iterator like iterable
	defineProperty(Iterator.prototype, Symbol.iterator.toString(), {
			value: function () {return this;},
			writable: true,
			configurable: true
	});

	simpleInheritance(ArrayIterator, Iterator);

	simpleInheritance(StringIterator, Iterator);

	defineProperty(ArrayIterator.prototype, Symbol.toStringTag.toString(), {
			value: "Array Iterator",
			configurable: true
	});

	defineProperty(StringIterator.prototype, Symbol.toStringTag.toString(), {
			value: "String Iterator",
			configurable: true
	});

	// This iterator works on any Array or TypedArray or array-like objects
	ArrayIterator.prototype.next = function next() {
			if (!(this instanceof ArrayIterator))
					throw new TypeError("Method Array Iterator.prototype.next called on incompatible receiver " + String(this));

			var self = this,
					nextValue;

			if (self._nextIndex === -1) {
					return {
							done: true,
							value: undefined
					};
			}

			if (!(typeof self._array.length === "number" && self._array.length >= 0)) {
					self._nextIndex = -1;
					return {
							done: true,
							value: undefined
					};
			}

			// _flag = 1 for [index, value]
			// _flag = 2 for [value]
			// _flag = 3 for [index]
			if (self._nextIndex < Math.floor(self._array.length)) {
					if (self._flag === 1)
							nextValue = [self._nextIndex, self._array[self._nextIndex]];
					else if (self._flag === 2)
							nextValue = self._array[self._nextIndex];
					else if (self._flag === 3)
							nextValue = self._nextIndex;
					self._nextIndex++;
					return {
							done: false,
							value: nextValue
					};
			} else {
					self._nextIndex = -1;
					return {
							done: true,
							value: undefined
					};
			}
	};

	StringIterator.prototype.next = function next() {
			if (!(this instanceof StringIterator))
					throw new TypeError("Method String Iterator.prototype.next called on incompatible receiver " + String(this));

			var self = this,
					stringObject = new String(this._string),
					nextValue;

			if (self._nextIndex === -1) {
					return {
							done: true,
							value: undefined
					};
			}

			if (self._nextIndex < stringObject.length) {
					nextValue = stringObject[self._nextIndex];
					self._nextIndex++;
					return {
							done: false,
							value: nextValue
					};
			} else {
					self._nextIndex = -1;
					return {
							done: true,
							value: undefined
					};
			}
	};

	var es6ArrayPrototypeIteratorSymbol = function values() {
			if (this === undefined || this === null)
					throw new TypeError("Cannot convert undefined or null to object");

			var self = Object(this);
			return new ArrayIterator(self, 2);
	};

	var es6StringPrototypeIteratorSymbol = function values() {
			if (this === undefined || this === null)
					throw new TypeError("String.prototype[Symbol.iterator] called on null or undefined");
			return new StringIterator(String(this), 0);
	};

	var es6ArrayPrototypeEntries = function entries() {
			if (this === undefined || this === null)
					throw new TypeError("Cannot convert undefined or null to object");

			var self = Object(this);
			return new ArrayIterator(self, 1);
	};

	var es6ArrayPrototypeKeys = function keys() {
			if (this === undefined || this === null)
					throw new TypeError("Cannot convert undefined or null to object");
			var self = Object(this);
			return new ArrayIterator(self, 3);
	};

	var SpreadOperatorImpl = function (target, thisArg) {
			this._target = target;
			this._values = [];
			this._thisArg = thisArg;
	};
	// All the arguments must be iterable
	SpreadOperatorImpl.prototype.spread = function () {
			var self = this;
			slice.call(arguments).forEach(function (iterable) {
					ES6.forOf(iterable, function (value) {
							self._values.push(value);
					});
			});
			return self;
	};

	SpreadOperatorImpl.prototype.add = function () {
			var self = this;
			slice.call(arguments).forEach(function (value) {
					self._values.push(value);
			});
			return self;
	};

	SpreadOperatorImpl.prototype.call = function (thisArg) {
			if (typeof this._target !== "function")
					throw new TypeError("Target is not a function");
			thisArg = arguments.length <= 0 ? this._thisArg : thisArg;
			return this._target.apply(thisArg, this._values);
	};

	SpreadOperatorImpl.prototype.new = function () {
			if (typeof this._target !== "function")
					throw new TypeError("Target is not a constructor");

			var temp,
					returnValue;
			temp = Object.create(this._target.prototype);
			returnValue = this._target.apply(temp, this._values);
			return isObject(returnValue) ? returnValue : temp;
	};

	// Affects the target array
	SpreadOperatorImpl.prototype.array = function () {
			if (!isArray(this._target))
					throw new TypeError("Target is not a array");
			push.apply(this._target, this._values);
			return this._target;
	};

	// Target must be Array or function
	var es6SpreadOperator = function spreadOperator(target, thisArg) {
			if (!(typeof target === "function" || isArray(target)))
					throw new TypeError("Spread operator only supports on array and function objects at this moment");
			return new SpreadOperatorImpl(target, thisArg);
	};

	var es6ArrayFrom = function from(arrayLike, mapFn, thisArg) {
			var constructor,
					i = 0,
					length,
					outputs;
			// Use the generic constructor
			constructor = !isConstructor(this) ? Array : this;
			if (arrayLike === undefined || arrayLike === null)
					throw new TypeError("Cannot convert undefined or null to object");

			arrayLike = Object(arrayLike);
			if (mapFn === undefined)
					mapFn = simpleFunction;
			else if (!isCallable(mapFn))
					throw new TypeError(mapFn + " is not a function");

			if (typeof arrayLike[Symbol.iterator] === "undefined") {
					if (!(typeof arrayLike.length === "number" && arrayLike.length >= 0)) {
							outputs = new constructor(0);
							outputs.length = 0;
							return outputs;
					}
					length = Math.floor(arrayLike.length);
					outputs = new constructor(length);
					outputs.length = length;
					for(; i < length; ++i)
							outputs[i] = mapFn.call(thisArg, arrayLike[i]);
			} else {
					outputs = new constructor();
					outputs.length = 0;
					ES6.forOf(arrayLike, function (value) {
							outputs.length++;
							outputs[outputs.length - 1] = mapFn.call(thisArg, value);
					});
			}
			return outputs;
	};

	// Export ES6 APIs and add all the patches to support Symbol in ES5
	// If the running environment already supports ES6 then no patches will be applied,
	if (isES6Running())
			return ES6;
	else {

			// Some ES6 APIs can't be implemented in pure ES5, so this 'ES6' object provides
			// some equivalent functionality of these features.
			defineProperties(ES6, {

					// Checks if a JS value is a symbol
					// It can be used as equivalent api in ES6: typeof symbol === 'symbol'
					isSymbol: {
							value: isSymbol,
							writable: true,
							configurable: true
					},

					// Native ES5 'instanceof' operator does not support @@hasInstance symbol,
					// this method provides same functionality of ES6 'instanceof' operator.
					instanceOf: {
							value: es6InstanceOfOperator,
							writable: true,
							configurable: true
					},

					// This method behaves exactly same as ES6 for...of loop.
					forOf: {
							value: es6ForOfLoop,
							writable: true,
							configurable: true
					},

					// This method gives same functionality of the spread operator of ES6
					// It works on only functions and arrays.
					// Limitation: You can't create array like this [...iterable, , , , 33] by this method,
					// to achieve this you have to do like this [...iterable, undefined, undefined, undefined, 33]
					spreadOperator: {
							value: es6SpreadOperator,
							writable: true,
							configurable: true
					}
			});

			defineProperty(global, "Symbol", {
					value: Symbol,
					writable: true,
					configurable: true
			});

			defineProperty(Function.prototype, Symbol.hasInstance.toString(), {
					value: es6FunctionPrototypeHasInstanceSymbol
			});

			defineProperty(Array.prototype, "concat", {
					value: es6ArrayPrototypeConcat,
					writable: true,
					configurable: true
			});

			defineProperty(Object.prototype, "toString", {
					value: es6ObjectPrototypeToString,
					writable: true,
					configurable: true
			});

			defineProperty(Array.prototype, Symbol.iterator.toString(), {
					value: es6ArrayPrototypeIteratorSymbol,
					writable: true,
					configurable: true
			});

			defineProperty(Array, "from", {
					value: es6ArrayFrom,
					writable: true,
					configurable: true
			});

			defineProperty(Array.prototype, "entries", {
					value: es6ArrayPrototypeEntries,
					writable: true,
					configurable: true
			});

			defineProperty(Array.prototype, "keys", {
					value: es6ArrayPrototypeKeys,
					writable: true,
					configurable: true
			});

			defineProperty(String.prototype, Symbol.iterator.toString(), {
					value: es6StringPrototypeIteratorSymbol,
					writable: true,
					configurable: true
			});
	}

	return ES6;
});