agenda-libre-ruby/public/webshims/shims/es6.js

// ES6-shim 0.8.0 (c) 2013 Paul Miller (paulmillr.com)
// ES6-shim may be freely distributed under the MIT license.
// For more details and documentation:
// https://github.com/paulmillr/es6-shim/
webshim.register('es6', function($, webshim, window, document, undefined){

	'use strict';

	var isCallableWithoutNew = function(func) {
		try { func(); }
		catch (e) { return false; }
		return true;
	};

	var supportsSubclassing = function(C, f) {
		/* jshint proto:true */
		try {
			var Sub = function() { C.apply(this, arguments); };
			if (!Sub.__proto__) { return false; /* skip test on IE < 11 */ }
			Object.setPrototypeOf(Sub, C);
			Sub.prototype = Object.create(C.prototype, {
				constructor: { value: C }
			});
			return f(Sub);
		} catch (e) {
			return false;
		}
	};

	var arePropertyDescriptorsSupported = function() {
		try {
			Object.defineProperty({}, 'x', {});
			return true;
		} catch (e) { /* this is IE 8. */
			return false;
		}
	};

	var startsWithRejectsRegex = function() {
		var rejectsRegex = false;
		if (String.prototype.startsWith) {
			try {
				'/a/'.startsWith(/a/);
			} catch (e) { /* this is spec compliant */
				rejectsRegex = true;
			}
		}
		return rejectsRegex;
	};

	/*jshint evil: true */
	var getGlobal = new Function('return this;');
	/*jshint evil: false */

	var main = function() {
		var globals = getGlobal();
		var global_isFinite = globals.isFinite;
		var supportsDescriptors = !!Object.defineProperty && arePropertyDescriptorsSupported();
		var startsWithIsCompliant = startsWithRejectsRegex();
		var _slice = Array.prototype.slice;
		var _indexOf = String.prototype.indexOf;
		var _toString = Object.prototype.toString;
		var _hasOwnProperty = Object.prototype.hasOwnProperty;
		var ArrayIterator; // make our implementation private

		// Define configurable, writable and non-enumerable props
		// if they don’t exist.
		var defineProperties = function(object, map) {
			Object.keys(map).forEach(function(name) {
				var method = map[name];
				if (name in object) return;
				if (supportsDescriptors) {
					Object.defineProperty(object, name, {
						configurable: true,
						enumerable: false,
						writable: true,
						value: method
					});
				} else {
					object[name] = method;
				}
			});
		};

		// Simple shim for Object.create on ES3 browsers
		// (unlike real shim, no attempt to support `prototype === null`)
		var create = Object.create || function(prototype, properties) {
			function Type() {}
			Type.prototype = prototype;
			var object = new Type();
			if (typeof properties !== "undefined") {
				defineProperties(object, properties);
			}
			return object;
		};

		// This is a private name in the es6 spec, equal to '[Symbol.iterator]'
		// we're going to use an arbitrary _-prefixed name to make our shims
		// work properly with each other, even though we don't have full Iterator
		// support.  That is, `Array.from(map.keys())` will work, but we don't
		// pretend to export a "real" Iterator interface.
		var $iterator$ = (typeof Symbol === 'object' && Symbol.iterator) ||
			'_es6shim_iterator_';
		// Firefox ships a partial implementation using the name @@iterator.
		// https://bugzilla.mozilla.org/show_bug.cgi?id=907077#c14
		// So use that name if we detect it.
		if (globals.Set && typeof new globals.Set()['@@iterator'] === 'function') {
			$iterator$ = '@@iterator';
		}
		var addIterator = function(prototype, impl) {
			if (!impl) { impl = function iterator() { return this; }; }
			var o = {};
			o[$iterator$] = impl;
			defineProperties(prototype, o);
		};

		// taken directly from https://github.com/ljharb/is-arguments/blob/master/index.js
		// can be replaced with require('is-arguments') if we ever use a build process instead
		var isArguments = function isArguments(value) {
			var str = _toString.call(value);
			var result = str === '[object Arguments]';
			if (!result) {
				result = str !== '[object Array]' &&
					value !== null &&
					typeof value === 'object' &&
					typeof value.length === 'number' &&
					value.length >= 0 &&
					_toString.call(value.callee) === '[object Function]';
			}
			return result;
		};

		var emulateES6construct = function(o) {
			if (!ES.TypeIsObject(o)) throw new TypeError('bad object');
			// es5 approximation to es6 subclass semantics: in es6, 'new Foo'
			// would invoke Foo.@@create to allocation/initialize the new object.
			// In es5 we just get the plain object.  So if we detect an
			// uninitialized object, invoke o.constructor.@@create
			if (!o._es6construct) {
				if (o.constructor && ES.IsCallable(o.constructor['@@create'])) {
					o = o.constructor['@@create'](o);
				}
				defineProperties(o, { _es6construct: true });
			}
			return o;
		};

		var ES = {
			CheckObjectCoercible: function(x, optMessage) {
				/* jshint eqnull:true */
				if (x == null)
					throw new TypeError(optMessage || ('Cannot call method on ' + x));
				return x;
			},

			TypeIsObject: function(x) {
				/* jshint eqnull:true */
				// this is expensive when it returns false; use this function
				// when you expect it to return true in the common case.
				return x != null && Object(x) === x;
			},

			ToObject: function(o, optMessage) {
				return Object(ES.CheckObjectCoercible(o, optMessage));
			},

			IsCallable: function(x) {
				return typeof x === 'function' &&
					// some versions of IE say that typeof /abc/ === 'function'
					_toString.call(x) === '[object Function]';
			},

			ToInt32: function(x) {
				return x >> 0;
			},

			ToUint32: function(x) {
				return x >>> 0;
			},

			ToInteger: function(value) {
				var number = +value;
				if (Number.isNaN(number)) return 0;
				if (number === 0 || !Number.isFinite(number)) return number;
				return Math.sign(number) * Math.floor(Math.abs(number));
			},

			ToLength: function(value) {
				var len = ES.ToInteger(value);
				if (len <= 0) return 0; // includes converting -0 to +0
				if (len > Number.MAX_SAFE_INTEGER) return Number.MAX_SAFE_INTEGER;
				return len;
			},

			SameValue: function(a, b) {
				if (a === b) {
					// 0 === -0, but they are not identical.
					if (a === 0) return 1 / a === 1 / b;
					return true;
				}
				return Number.isNaN(a) && Number.isNaN(b);
			},

			SameValueZero: function(a, b) {
				// same as SameValue except for SameValueZero(+0, -0) == true
				return (a === b) || (Number.isNaN(a) && Number.isNaN(b));
			},

			IsIterable: function(o) {
				return ES.TypeIsObject(o) &&
					(o[$iterator$] !== undefined || isArguments(o));
			},

			GetIterator: function(o) {
				if (isArguments(o)) {
					// special case support for `arguments`
					return new ArrayIterator(o, "value");
				}
				var it = o[$iterator$]();
				if (!ES.TypeIsObject(it)) {
					throw new TypeError('bad iterator');
				}
				return it;
			},

			IteratorNext: function(it) {
				var result = (arguments.length > 1) ? it.next(arguments[1]) : it.next();
				if (!ES.TypeIsObject(result)) {
					throw new TypeError('bad iterator');
				}
				return result;
			},

			Construct: function(C, args) {
				// CreateFromConstructor
				var obj;
				if (ES.IsCallable(C['@@create'])) {
					obj = C['@@create']();
				} else {
					// OrdinaryCreateFromConstructor
					obj = create(C.prototype || null);
				}
				// Mark that we've used the es6 construct path
				// (see emulateES6construct)
				defineProperties(obj, { _es6construct: true });
				// Call the constructor.
				var result = C.apply(obj, args);
				return ES.TypeIsObject(result) ? result : obj;
			}
		};

		var numberConversion = (function () {
			// from https://github.com/inexorabletash/polyfill/blob/master/typedarray.js#L176-L266
			// with permission and license, per https://twitter.com/inexorabletash/status/372206509540659200

			function roundToEven(n) {
				var w = Math.floor(n), f = n - w;
				if (f < 0.5) {
					return w;
				}
				if (f > 0.5) {
					return w + 1;
				}
				return w % 2 ? w + 1 : w;
			}

			function packIEEE754(v, ebits, fbits) {
				var bias = (1 << (ebits - 1)) - 1,
					s, e, f, ln,
					i, bits, str, bytes;

				// Compute sign, exponent, fraction
				if (v !== v) {
					// NaN
					// http://dev.w3.org/2006/webapi/WebIDL/#es-type-mapping
					e = (1 << ebits) - 1;
					f = Math.pow(2, fbits - 1);
					s = 0;
				} else if (v === Infinity || v === -Infinity) {
					e = (1 << ebits) - 1;
					f = 0;
					s = (v < 0) ? 1 : 0;
				} else if (v === 0) {
					e = 0;
					f = 0;
					s = (1 / v === -Infinity) ? 1 : 0;
				} else {
					s = v < 0;
					v = Math.abs(v);

					if (v >= Math.pow(2, 1 - bias)) {
						e = Math.min(Math.floor(Math.log(v) / Math.LN2), 1023);
						f = roundToEven(v / Math.pow(2, e) * Math.pow(2, fbits));
						if (f / Math.pow(2, fbits) >= 2) {
							e = e + 1;
							f = 1;
						}
						if (e > bias) {
							// Overflow
							e = (1 << ebits) - 1;
							f = 0;
						} else {
							// Normal
							e = e + bias;
							f = f - Math.pow(2, fbits);
						}
					} else {
						// Subnormal
						e = 0;
						f = roundToEven(v / Math.pow(2, 1 - bias - fbits));
					}
				}

				// Pack sign, exponent, fraction
				bits = [];
				for (i = fbits; i; i -= 1) {
					bits.push(f % 2 ? 1 : 0);
					f = Math.floor(f / 2);
				}
				for (i = ebits; i; i -= 1) {
					bits.push(e % 2 ? 1 : 0);
					e = Math.floor(e / 2);
				}
				bits.push(s ? 1 : 0);
				bits.reverse();
				str = bits.join('');

				// Bits to bytes
				bytes = [];
				while (str.length) {
					bytes.push(parseInt(str.substring(0, 8), 2));
					str = str.substring(8);
				}
				return bytes;
			}

			function unpackIEEE754(bytes, ebits, fbits) {
				// Bytes to bits
				var bits = [], i, j, b, str,
					bias, s, e, f;

				for (i = bytes.length; i; i -= 1) {
					b = bytes[i - 1];
					for (j = 8; j; j -= 1) {
						bits.push(b % 2 ? 1 : 0);
						b = b >> 1;
					}
				}
				bits.reverse();
				str = bits.join('');

				// Unpack sign, exponent, fraction
				bias = (1 << (ebits - 1)) - 1;
				s = parseInt(str.substring(0, 1), 2) ? -1 : 1;
				e = parseInt(str.substring(1, 1 + ebits), 2);
				f = parseInt(str.substring(1 + ebits), 2);

				// Produce number
				if (e === (1 << ebits) - 1) {
					return f !== 0 ? NaN : s * Infinity;
				} else if (e > 0) {
					// Normalized
					return s * Math.pow(2, e - bias) * (1 + f / Math.pow(2, fbits));
				} else if (f !== 0) {
					// Denormalized
					return s * Math.pow(2, -(bias - 1)) * (f / Math.pow(2, fbits));
				} else {
					return s < 0 ? -0 : 0;
				}
			}

			function unpackFloat64(b) { return unpackIEEE754(b, 11, 52); }
			function packFloat64(v) { return packIEEE754(v, 11, 52); }
			function unpackFloat32(b) { return unpackIEEE754(b, 8, 23); }
			function packFloat32(v) { return packIEEE754(v, 8, 23); }

			var conversions = {
				toFloat32: function (num) { return unpackFloat32(packFloat32(num)); }
			};
			if (typeof Float32Array !== 'undefined') {
				var float32array = new Float32Array(1);
				conversions.toFloat32 = function (num) {
					float32array[0] = num;
					return float32array[0];
				};
			}
			return conversions;
		}());

		defineProperties(String, {
			fromCodePoint: function() {
				var points = _slice.call(arguments, 0, arguments.length);
				var result = [];
				var next;
				for (var i = 0, length = points.length; i < length; i++) {
					next = Number(points[i]);
					if (!ES.SameValue(next, ES.ToInteger(next)) ||
						next < 0 || next > 0x10FFFF) {
						throw new RangeError('Invalid code point ' + next);
					}

					if (next < 0x10000) {
						result.push(String.fromCharCode(next));
					} else {
						next -= 0x10000;
						result.push(String.fromCharCode((next >> 10) + 0xD800));
						result.push(String.fromCharCode((next % 0x400) + 0xDC00));
					}
				}
				return result.join('');
			},

			raw: function(callSite) { // raw.length===1
				var substitutions = _slice.call(arguments, 1, arguments.length);
				var cooked = ES.ToObject(callSite, 'bad callSite');
				var rawValue = cooked.raw;
				var raw = ES.ToObject(rawValue, 'bad raw value');
				var len = Object.keys(raw).length;
				var literalsegments = ES.ToLength(len);
				if (literalsegments === 0) {
					return '';
				}

				var stringElements = [];
				var nextIndex = 0;
				var nextKey, next, nextSeg, nextSub;
				while (nextIndex < literalsegments) {
					nextKey = String(nextIndex);
					next = raw[nextKey];
					nextSeg = String(next);
					stringElements.push(nextSeg);
					if (nextIndex + 1 >= literalsegments) {
						break;
					}
					next = substitutions[nextKey];
					if (next === undefined) {
						break;
					}
					nextSub = String(next);
					stringElements.push(nextSub);
					nextIndex++;
				}
				return stringElements.join('');
			}
		});

		var StringShims = {
			// Fast repeat, uses the `Exponentiation by squaring` algorithm.
			// Perf: http://jsperf.com/string-repeat2/2
			repeat: (function() {
				var repeat = function(s, times) {
					if (times < 1) return '';
					if (times % 2) return repeat(s, times - 1) + s;
					var half = repeat(s, times / 2);
					return half + half;
				};

				return function(times) {
					var thisStr = String(ES.CheckObjectCoercible(this));
					times = ES.ToInteger(times);
					if (times < 0 || times === Infinity) {
						throw new RangeError('Invalid String#repeat value');
					}
					return repeat(thisStr, times);
				};
			})(),

			startsWith: function(searchStr) {
				var thisStr = String(ES.CheckObjectCoercible(this));
				if (_toString.call(searchStr) === '[object RegExp]') throw new TypeError('Cannot call method "startsWith" with a regex');
				searchStr = String(searchStr);
				var startArg = arguments.length > 1 ? arguments[1] : undefined;
				var start = Math.max(ES.ToInteger(startArg), 0);
				return thisStr.slice(start, start + searchStr.length) === searchStr;
			},

			endsWith: function(searchStr) {
				var thisStr = String(ES.CheckObjectCoercible(this));
				if (_toString.call(searchStr) === '[object RegExp]') throw new TypeError('Cannot call method "endsWith" with a regex');
				searchStr = String(searchStr);
				var thisLen = thisStr.length;
				var posArg = arguments.length > 1 ? arguments[1] : undefined;
				var pos = posArg === undefined ? thisLen : ES.ToInteger(posArg);
				var end = Math.min(Math.max(pos, 0), thisLen);
				return thisStr.slice(end - searchStr.length, end) === searchStr;
			},

			contains: function(searchString) {
				var position = arguments.length > 1 ? arguments[1] : undefined;
				// Somehow this trick makes method 100% compat with the spec.
				return _indexOf.call(this, searchString, position) !== -1;
			},

			codePointAt: function(pos) {
				var thisStr = String(ES.CheckObjectCoercible(this));
				var position = ES.ToInteger(pos);
				var length = thisStr.length;
				if (position < 0 || position >= length) return undefined;
				var first = thisStr.charCodeAt(position);
				var isEnd = (position + 1 === length);
				if (first < 0xD800 || first > 0xDBFF || isEnd) return first;
				var second = thisStr.charCodeAt(position + 1);
				if (second < 0xDC00 || second > 0xDFFF) return first;
				return ((first - 0xD800) * 1024) + (second - 0xDC00) + 0x10000;
			}
		};
		defineProperties(String.prototype, StringShims);

		var hasStringTrimBug = '\u0085'.trim().length !== 1;
		if (hasStringTrimBug) {
			var originalStringTrim = String.prototype.trim;
			delete String.prototype.trim;
			// whitespace from: http://es5.github.io/#x15.5.4.20
			// implementation from https://github.com/es-shims/es5-shim/blob/v3.4.0/es5-shim.js#L1304-L1324
			var ws = [
				'\x09\x0A\x0B\x0C\x0D\x20\xA0\u1680\u180E\u2000\u2001\u2002\u2003',
				'\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000\u2028',
				'\u2029\uFEFF'
			].join('');
			var trimBeginRegexp = new RegExp('^[' + ws + '][' + ws + ']*');
			var trimEndRegexp = new RegExp('[' + ws + '][' + ws + ']*$');
			defineProperties(String.prototype, {
				trim: function() {
					if (this === undefined || this === null) {
						throw new TypeError("can't convert " + this + " to object");
					}
					return String(this)
						.replace(trimBeginRegexp, "")
						.replace(trimEndRegexp, "");
				}
			});
		}

		// see https://people.mozilla.org/~jorendorff/es6-draft.html#sec-string.prototype-@@iterator
		var StringIterator = function(s) {
			this._s = String(ES.CheckObjectCoercible(s));
			this._i = 0;
		};
		StringIterator.prototype.next = function() {
			var s = this._s, i = this._i;
			if (s === undefined || i >= s.length) {
				this._s = undefined;
				return { value: undefined, done: true };
			}
			var first = s.charCodeAt(i), second, len;
			if (first < 0xD800 || first > 0xDBFF || (i+1) == s.length) {
				len = 1;
			} else {
				second = s.charCodeAt(i+1);
				len = (second < 0xDC00 || second > 0xDFFF) ? 1 : 2;
			}
			this._i = i + len;
			return { value: s.substr(i, len), done: false };
		};
		addIterator(StringIterator.prototype);
		addIterator(String.prototype, function() {
			return new StringIterator(this);
		});

		if (!startsWithIsCompliant) {
			// Firefox has a noncompliant startsWith implementation
			String.prototype.startsWith = StringShims.startsWith;
			String.prototype.endsWith = StringShims.endsWith;
		}

		defineProperties(Array, {
			from: function(iterable) {
				var mapFn = arguments.length > 1 ? arguments[1] : undefined;
				var thisArg = arguments.length > 2 ? arguments[2] : undefined;

				var list = ES.ToObject(iterable, 'bad iterable');
				if (mapFn !== undefined && !ES.IsCallable(mapFn)) {
					throw new TypeError('Array.from: when provided, the second argument must be a function');
				}

				var usingIterator = ES.IsIterable(list);
				// does the spec really mean that Arrays should use ArrayIterator?
				// https://bugs.ecmascript.org/show_bug.cgi?id=2416
				//if (Array.isArray(list)) { usingIterator=false; }
				var length = usingIterator ? 0 : ES.ToLength(list.length);
				var result = ES.IsCallable(this) ? Object(usingIterator ? new this() : new this(length)) : new Array(length);
				var it = usingIterator ? ES.GetIterator(list) : null;
				var value;

				for (var i = 0; usingIterator || (i < length); i++) {
					if (usingIterator) {
						value = ES.IteratorNext(it);
						if (value.done) {
							length = i;
							break;
						}
						value = value.value;
					} else {
						value = list[i];
					}
					if (mapFn) {
						result[i] = thisArg ? mapFn.call(thisArg, value, i) : mapFn(value, i);
					} else {
						result[i] = value;
					}
				}

				result.length = length;
				return result;
			},

			of: function() {
				return Array.from(arguments);
			}
		});

		// Our ArrayIterator is private; see
		// https://github.com/paulmillr/es6-shim/issues/252
		ArrayIterator = function(array, kind) {
			this.i = 0;
			this.array = array;
			this.kind = kind;
		};

		defineProperties(ArrayIterator.prototype, {
			next: function() {
				var i = this.i, array = this.array;
				if (i === undefined || this.kind === undefined) {
					throw new TypeError('Not an ArrayIterator');
				}
				if (array!==undefined) {
					var len = ES.ToLength(array.length);
					for (; i < len; i++) {
						var kind = this.kind;
						var retval;
						if (kind === "key") {
							retval = i;
						} else if (kind === "value") {
							retval = array[i];
						} else if (kind === "entry") {
							retval = [i, array[i]];
						}
						this.i = i + 1;
						return { value: retval, done: false };
					}
				}
				this.array = undefined;
				return { value: undefined, done: true };
			}
		});
		addIterator(ArrayIterator.prototype);

		defineProperties(Array.prototype, {
			copyWithin: function(target, start) {
				var end = arguments[2]; // copyWithin.length must be 2
				var o = ES.ToObject(this);
				var len = ES.ToLength(o.length);
				target = ES.ToInteger(target);
				start = ES.ToInteger(start);
				var to = target < 0 ? Math.max(len + target, 0) : Math.min(target, len);
				var from = start < 0 ? Math.max(len + start, 0) : Math.min(start, len);
				end = (end===undefined) ? len : ES.ToInteger(end);
				var fin = end < 0 ? Math.max(len + end, 0) : Math.min(end, len);
				var count = Math.min(fin - from, len - to);
				var direction = 1;
				if (from < to && to < (from + count)) {
					direction = -1;
					from += count - 1;
					to += count - 1;
				}
				while (count > 0) {
					if (_hasOwnProperty.call(o, from)) {
						o[to] = o[from];
					} else {
						delete o[from];
					}
					from += direction;
					to += direction;
					count -= 1;
				}
				return o;
			},

			fill: function(value) {
				var start = arguments[1], end = arguments[2]; // fill.length===1
				var O = ES.ToObject(this);
				var len = ES.ToLength(O.length);
				start = ES.ToInteger(start===undefined ? 0 : start);
				end = ES.ToInteger(end===undefined ? len : end);

				var relativeStart = start < 0 ? Math.max(len + start, 0) : Math.min(start, len);

				for (var i = relativeStart; i < len && i < end; ++i) {
					O[i] = value;
				}
				return O;
			},

			find: function(predicate) {
				var list = ES.ToObject(this);
				var length = ES.ToLength(list.length);
				if (!ES.IsCallable(predicate)) {
					throw new TypeError('Array#find: predicate must be a function');
				}
				var thisArg = arguments[1];
				for (var i = 0, value; i < length; i++) {
					if (i in list) {
						value = list[i];
						if (predicate.call(thisArg, value, i, list)) return value;
					}
				}
				return undefined;
			},

			findIndex: function(predicate) {
				var list = ES.ToObject(this);
				var length = ES.ToLength(list.length);
				if (!ES.IsCallable(predicate)) {
					throw new TypeError('Array#findIndex: predicate must be a function');
				}
				var thisArg = arguments[1];
				for (var i = 0; i < length; i++) {
					if (i in list) {
						if (predicate.call(thisArg, list[i], i, list)) return i;
					}
				}
				return -1;
			},

			keys: function() {
				return new ArrayIterator(this, "key");
			},

			values: function() {
				return new ArrayIterator(this, "value");
			},

			entries: function() {
				return new ArrayIterator(this, "entry");
			}
		});
		addIterator(Array.prototype, function() { return this.values(); });
		// Chrome defines keys/values/entries on Array, but doesn't give us
		// any way to identify its iterator.  So add our own shimmed field.
		if (Object.getPrototypeOf) {
			addIterator(Object.getPrototypeOf([].values()));
		}

		var maxSafeInteger = Math.pow(2, 53) - 1;
		defineProperties(Number, {
			MAX_SAFE_INTEGER: maxSafeInteger,
			MIN_SAFE_INTEGER: -maxSafeInteger,
			EPSILON: 2.220446049250313e-16,

			parseInt: globals.parseInt,
			parseFloat: globals.parseFloat,

			isFinite: function(value) {
				return typeof value === 'number' && global_isFinite(value);
			},

			isInteger: function(value) {
				return typeof value === 'number' &&
					!Number.isNaN(value) &&
					Number.isFinite(value) &&
					ES.ToInteger(value) === value;
			},

			isSafeInteger: function(value) {
				return Number.isInteger(value) && Math.abs(value) <= Number.MAX_SAFE_INTEGER;
			},

			isNaN: function(value) {
				// NaN !== NaN, but they are identical.
				// NaNs are the only non-reflexive value, i.e., if x !== x,
				// then x is NaN.
				// isNaN is broken: it converts its argument to number, so
				// isNaN('foo') => true
				return value !== value;
			}

		});

		if (supportsDescriptors) {
			defineProperties(Object, {
				getPropertyDescriptor: function(subject, name) {
					var pd = Object.getOwnPropertyDescriptor(subject, name);
					var proto = Object.getPrototypeOf(subject);
					while (pd === undefined && proto !== null) {
						pd = Object.getOwnPropertyDescriptor(proto, name);
						proto = Object.getPrototypeOf(proto);
					}
					return pd;
				},

				getPropertyNames: function(subject) {
					var result = Object.getOwnPropertyNames(subject);
					var proto = Object.getPrototypeOf(subject);

					var addProperty = function(property) {
						if (result.indexOf(property) === -1) {
							result.push(property);
						}
					};

					while (proto !== null) {
						Object.getOwnPropertyNames(proto).forEach(addProperty);
						proto = Object.getPrototypeOf(proto);
					}
					return result;
				}
			});

			defineProperties(Object, {
				// 19.1.3.1
				assign: function(target, source) {
					if (!ES.TypeIsObject(target)) {
						throw new TypeError('target must be an object');
					}
					return Array.prototype.reduce.call(arguments, function(target, source) {
						if (!ES.TypeIsObject(source)) {
							throw new TypeError('source must be an object');
						}
						return Object.keys(source).reduce(function(target, key) {
							target[key] = source[key];
							return target;
						}, target);
					});
				},

				getOwnPropertyKeys: function(subject) {
					return Object.keys(subject);
				},

				is: function(a, b) {
					return ES.SameValue(a, b);
				},

				// 19.1.3.9
				// shim from https://gist.github.com/WebReflection/5593554
				setPrototypeOf: (function(Object, magic) {
					var set;

					var checkArgs = function(O, proto) {
						if (!ES.TypeIsObject(O)) {
							throw new TypeError('cannot set prototype on a non-object');
						}
						if (!(proto===null || ES.TypeIsObject(proto))) {
							throw new TypeError('can only set prototype to an object or null'+proto);
						}
					};

					var setPrototypeOf = function(O, proto) {
						checkArgs(O, proto);
						set.call(O, proto);
						return O;
					};

					try {
						// this works already in Firefox and Safari
						set = Object.getOwnPropertyDescriptor(Object.prototype, magic).set;
						set.call({}, null);
					} catch (e) {
						if (Object.prototype !== {}[magic]) {
							// IE < 11 cannot be shimmed
							return;
						}
						// probably Chrome or some old Mobile stock browser
						set = function(proto) {
							this[magic] = proto;
						};
						// please note that this will **not** work
						// in those browsers that do not inherit
						// __proto__ by mistake from Object.prototype
						// in these cases we should probably throw an error
						// or at least be informed about the issue
						setPrototypeOf.polyfill = setPrototypeOf(
							setPrototypeOf({}, null),
							Object.prototype
						) instanceof Object;
						// setPrototypeOf.polyfill === true means it works as meant
						// setPrototypeOf.polyfill === false means it's not 100% reliable
						// setPrototypeOf.polyfill === undefined
						// or
						// setPrototypeOf.polyfill ==  null means it's not a polyfill
						// which means it works as expected
						// we can even delete Object.prototype.__proto__;
					}
					return setPrototypeOf;
				})(Object, '__proto__')
			});
		}

		// Workaround bug in Opera 12 where setPrototypeOf(x, null) doesn't work,
		// but Object.create(null) does.
		if (Object.setPrototypeOf && Object.getPrototypeOf &&
			Object.getPrototypeOf(Object.setPrototypeOf({}, null)) !== null &&
			Object.getPrototypeOf(Object.create(null)) === null) {
			(function() {
				var FAKENULL = Object.create(null);
				var gpo = Object.getPrototypeOf, spo = Object.setPrototypeOf;
				Object.getPrototypeOf = function(o) {
					var result = gpo(o);
					return result === FAKENULL ? null : result;
				};
				Object.setPrototypeOf = function(o, p) {
					if (p === null) { p = FAKENULL; }
					return spo(o, p);
				};
				Object.setPrototypeOf.polyfill = false;
			})();
		}

		try {
			Object.keys('foo');
		} catch (e) {
			var originalObjectKeys = Object.keys;
			Object.keys = function (obj) {
				return originalObjectKeys(ES.ToObject(obj));
			};
		}

		var MathShims = {
			acosh: function(value) {
				value = Number(value);
				if (Number.isNaN(value) || value < 1) return NaN;
				if (value === 1) return 0;
				if (value === Infinity) return value;
				return Math.log(value + Math.sqrt(value * value - 1));
			},

			asinh: function(value) {
				value = Number(value);
				if (value === 0 || !global_isFinite(value)) {
					return value;
				}
				return value < 0 ? -Math.asinh(-value) : Math.log(value + Math.sqrt(value * value + 1));
			},

			atanh: function(value) {
				value = Number(value);
				if (Number.isNaN(value) || value < -1 || value > 1) {
					return NaN;
				}
				if (value === -1) return -Infinity;
				if (value === 1) return Infinity;
				if (value === 0) return value;
				return 0.5 * Math.log((1 + value) / (1 - value));
			},

			cbrt: function(value) {
				value = Number(value);
				if (value === 0) return value;
				var negate = value < 0, result;
				if (negate) value = -value;
				result = Math.pow(value, 1/3);
				return negate ? -result : result;
			},

			clz32: function(value) {
				// See https://bugs.ecmascript.org/show_bug.cgi?id=2465
				value = Number(value);
				if (Number.isNaN(value)) return NaN;
				var number = ES.ToUint32(value);
				if (number === 0) {
					return 32;
				}
				return 32 - (number).toString(2).length;
			},

			cosh: function(value) {
				value = Number(value);
				if (value === 0) return 1; // +0 or -0
				if (Number.isNaN(value)) return NaN;
				if (!global_isFinite(value)) return Infinity;
				if (value < 0) value = -value;
				if (value > 21) return Math.exp(value) / 2;
				return (Math.exp(value) + Math.exp(-value)) / 2;
			},

			expm1: function(value) {
				value = Number(value);
				if (value === -Infinity) return -1;
				if (!global_isFinite(value) || value === 0) return value;
				return Math.exp(value) - 1;
			},

			hypot: function(x, y) {
				var anyNaN = false;
				var allZero = true;
				var anyInfinity = false;
				var numbers = [];
				Array.prototype.every.call(arguments, function(arg) {
					var num = Number(arg);
					if (Number.isNaN(num)) anyNaN = true;
					else if (num === Infinity || num === -Infinity) anyInfinity = true;
					else if (num !== 0) allZero = false;
					if (anyInfinity) {
						return false;
					} else if (!anyNaN) {
						numbers.push(Math.abs(num));
					}
					return true;
				});
				if (anyInfinity) return Infinity;
				if (anyNaN) return NaN;
				if (allZero) return 0;

				numbers.sort(function (a, b) { return b - a; });
				var largest = numbers[0];
				var divided = numbers.map(function (number) { return number / largest; });
				var sum = divided.reduce(function (sum, number) { return sum += number * number; }, 0);
				return largest * Math.sqrt(sum);
			},

			log2: function(value) {
				return Math.log(value) * Math.LOG2E;
			},

			log10: function(value) {
				return Math.log(value) * Math.LOG10E;
			},

			log1p: function(value) {
				value = Number(value);
				if (value < -1 || Number.isNaN(value)) return NaN;
				if (value === 0 || value === Infinity) return value;
				if (value === -1) return -Infinity;
				var result = 0;
				var n = 50;

				if (value < 0 || value > 1) return Math.log(1 + value);
				for (var i = 1; i < n; i++) {
					if ((i % 2) === 0) {
						result -= Math.pow(value, i) / i;
					} else {
						result += Math.pow(value, i) / i;
					}
				}

				return result;
			},

			sign: function(value) {
				var number = +value;
				if (number === 0) return number;
				if (Number.isNaN(number)) return number;
				return number < 0 ? -1 : 1;
			},

			sinh: function(value) {
				value = Number(value);
				if (!global_isFinite(value) || value === 0) return value;
				return (Math.exp(value) - Math.exp(-value)) / 2;
			},

			tanh: function(value) {
				value = Number(value);
				if (Number.isNaN(value) || value === 0) return value;
				if (value === Infinity) return 1;
				if (value === -Infinity) return -1;
				return (Math.exp(value) - Math.exp(-value)) / (Math.exp(value) + Math.exp(-value));
			},

			trunc: function(value) {
				var number = Number(value);
				return number < 0 ? -Math.floor(-number) : Math.floor(number);
			},

			imul: function(x, y) {
				// taken from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/imul
				var ah  = (x >>> 16) & 0xffff;
				var al = x & 0xffff;
				var bh  = (y >>> 16) & 0xffff;
				var bl = y & 0xffff;
				// the shift by 0 fixes the sign on the high part
				// the final |0 converts the unsigned value into a signed value
				return ((al * bl) + (((ah * bl + al * bh) << 16) >>> 0)|0);
			},

			fround: function(x) {
				if (x === 0 || x === Infinity || x === -Infinity || Number.isNaN(x)) {
					return x;
				}
				var num = Number(x);
				return numberConversion.toFloat32(num);
			}
		};
		defineProperties(Math, MathShims);

		if (Math.imul(0xffffffff, 5) !== -5) {
			// Safari 6.1, at least, reports "0" for this value
			Math.imul = MathShims.imul;
		}

		// Promises
		// Simplest possible implementation; use a 3rd-party library if you
		// want the best possible speed and/or long stack traces.
		var PromiseShim = (function() {

			var Promise, Promise$prototype;

			ES.IsPromise = function(promise) {
				if (!ES.TypeIsObject(promise)) {
					return false;
				}
				if (!promise._promiseConstructor) {
					// _promiseConstructor is a bit more unique than _status, so we'll
					// check that instead of the [[PromiseStatus]] internal field.
					return false;
				}
				if (promise._status === undefined) {
					return false; // uninitialized
				}
				return true;
			};

			// "PromiseCapability" in the spec is what most promise implementations
			// call a "deferred".
			var PromiseCapability = function(C) {
				if (!ES.IsCallable(C)) {
					throw new TypeError('bad promise constructor');
				}
				var capability = this;
				var resolver = function(resolve, reject) {
					capability.resolve = resolve;
					capability.reject = reject;
				};
				capability.promise = ES.Construct(C, [resolver]);
				// see https://bugs.ecmascript.org/show_bug.cgi?id=2478
				if (!capability.promise._es6construct) {
					throw new TypeError('bad promise constructor');
				}
				if (!(ES.IsCallable(capability.resolve) &&
					ES.IsCallable(capability.reject))) {
					throw new TypeError('bad promise constructor');
				}
			};

			// find an appropriate setImmediate-alike
			var setTimeout = globals.setTimeout;
			var makeZeroTimeout;
			if (typeof window !== 'undefined' && ES.IsCallable(window.postMessage)) {
				makeZeroTimeout = function() {
					// from http://dbaron.org/log/20100309-faster-timeouts
					var timeouts = [];
					var messageName = "zero-timeout-message";
					var setZeroTimeout = function(fn) {
						timeouts.push(fn);
						window.postMessage(messageName, "*");
					};
					var handleMessage = function(event) {
						if (event.source == window && event.data == messageName) {
							event.stopPropagation();
							if (timeouts.length === 0) { return; }
							var fn = timeouts.shift();
							fn();
						}
					};
					window.addEventListener("message", handleMessage, true);
					return setZeroTimeout;
				};
			}
			var makePromiseAsap = function() {
				// An efficient task-scheduler based on a pre-existing Promise
				// implementation, which we can use even if we override the
				// global Promise below (in order to workaround bugs)
				// https://github.com/Raynos/observ-hash/issues/2#issuecomment-35857671
				var P = globals.Promise;
				return P && P.resolve && function(task) {
					return P.resolve().then(task);
				};
			};
			var enqueue = ES.IsCallable(globals.setImmediate) ?
				globals.setImmediate.bind(globals) :
				typeof process === 'object' && process.nextTick ? process.nextTick :
					makePromiseAsap() ||
						(ES.IsCallable(makeZeroTimeout) ? makeZeroTimeout() :
							function(task) { setTimeout(task, 0); }); // fallback

			var triggerPromiseReactions = function(reactions, x) {
				reactions.forEach(function(reaction) {
					enqueue(function() {
						// PromiseReactionTask
						var handler = reaction.handler;
						var capability = reaction.capability;
						var resolve = capability.resolve;
						var reject = capability.reject;
						try {
							var result = handler(x);
							if (result === capability.promise) {
								throw new TypeError('self resolution');
							}
							var updateResult =
								updatePromiseFromPotentialThenable(result, capability);
							if (!updateResult) {
								resolve(result);
							}
						} catch (e) {
							reject(e);
						}
					});
				});
			};

			var updatePromiseFromPotentialThenable = function(x, capability) {
				if (!ES.TypeIsObject(x)) {
					return false;
				}
				var resolve = capability.resolve;
				var reject = capability.reject;
				try {
					var then = x.then; // only one invocation of accessor
					if (!ES.IsCallable(then)) { return false; }
					then.call(x, resolve, reject);
				} catch(e) {
					reject(e);
				}
				return true;
			};

			var promiseResolutionHandler = function(promise, onFulfilled, onRejected){
				return function(x) {
					if (x === promise) {
						return onRejected(new TypeError('self resolution'));
					}
					var C = promise._promiseConstructor;
					var capability = new PromiseCapability(C);
					var updateResult = updatePromiseFromPotentialThenable(x, capability);
					if (updateResult) {
						return capability.promise.then(onFulfilled, onRejected);
					} else {
						return onFulfilled(x);
					}
				};
			};

			Promise = function(resolver) {
				var promise = this;
				promise = emulateES6construct(promise);
				if (!promise._promiseConstructor) {
					// we use _promiseConstructor as a stand-in for the internal
					// [[PromiseStatus]] field; it's a little more unique.
					throw new TypeError('bad promise');
				}
				if (promise._status !== undefined) {
					throw new TypeError('promise already initialized');
				}
				// see https://bugs.ecmascript.org/show_bug.cgi?id=2482
				if (!ES.IsCallable(resolver)) {
					throw new TypeError('not a valid resolver');
				}
				promise._status = 'unresolved';
				promise._resolveReactions = [];
				promise._rejectReactions = [];

				var resolve = function(resolution) {
					if (promise._status !== 'unresolved') { return; }
					var reactions = promise._resolveReactions;
					promise._result = resolution;
					promise._resolveReactions = undefined;
					promise._rejectReactions = undefined;
					promise._status = 'has-resolution';
					triggerPromiseReactions(reactions, resolution);
				};
				var reject = function(reason) {
					if (promise._status !== 'unresolved') { return; }
					var reactions = promise._rejectReactions;
					promise._result = reason;
					promise._resolveReactions = undefined;
					promise._rejectReactions = undefined;
					promise._status = 'has-rejection';
					triggerPromiseReactions(reactions, reason);
				};
				try {
					resolver(resolve, reject);
				} catch (e) {
					reject(e);
				}
				return promise;
			};
			Promise$prototype = Promise.prototype;
			defineProperties(Promise, {
				'@@create': function(obj) {
					var constructor = this;
					// AllocatePromise
					// The `obj` parameter is a hack we use for es5
					// compatibility.
					var prototype = constructor.prototype || Promise$prototype;
					obj = obj || create(prototype);
					defineProperties(obj, {
						_status: undefined,
						_result: undefined,
						_resolveReactions: undefined,
						_rejectReactions: undefined,
						_promiseConstructor: undefined
					});
					obj._promiseConstructor = constructor;
					return obj;
				}
			});

			var _promiseAllResolver = function(index, values, capability, remaining) {
				var done = false;
				return function(x) {
					if (done) { return; } // protect against being called multiple times
					done = true;
					values[index] = x;
					if ((--remaining.count) === 0) {
						var resolve = capability.resolve;
						resolve(values); // call w/ this===undefined
					}
				};
			};

			Promise.all = function(iterable) {
				var C = this;
				var capability = new PromiseCapability(C);
				var resolve = capability.resolve;
				var reject = capability.reject;
				try {
					if (!ES.IsIterable(iterable)) {
						throw new TypeError('bad iterable');
					}
					var it = ES.GetIterator(iterable);
					var values = [], remaining = { count: 1 };
					for (var index = 0; ; index++) {
						var next = ES.IteratorNext(it);
						if (next.done) {
							break;
						}
						var nextPromise = C.resolve(next.value);
						var resolveElement = _promiseAllResolver(
							index, values, capability, remaining
						);
						remaining.count++;
						nextPromise.then(resolveElement, capability.reject);
					}
					if ((--remaining.count) === 0) {
						resolve(values); // call w/ this===undefined
					}
				} catch (e) {
					reject(e);
				}
				return capability.promise;
			};

			Promise.race = function(iterable) {
				var C = this;
				var capability = new PromiseCapability(C);
				var resolve = capability.resolve;
				var reject = capability.reject;
				try {
					if (!ES.IsIterable(iterable)) {
						throw new TypeError('bad iterable');
					}
					var it = ES.GetIterator(iterable);
					while (true) {
						var next = ES.IteratorNext(it);
						if (next.done) {
							// If iterable has no items, resulting promise will never
							// resolve; see:
							// https://github.com/domenic/promises-unwrapping/issues/75
							// https://bugs.ecmascript.org/show_bug.cgi?id=2515
							break;
						}
						var nextPromise = C.resolve(next.value);
						nextPromise.then(resolve, reject);
					}
				} catch (e) {
					reject(e);
				}
				return capability.promise;
			};

			Promise.reject = function(reason) {
				var C = this;
				var capability = new PromiseCapability(C);
				var reject = capability.reject;
				reject(reason); // call with this===undefined
				return capability.promise;
			};

			Promise.resolve = function(v) {
				var C = this;
				if (ES.IsPromise(v)) {
					var constructor = v._promiseConstructor;
					if (constructor === C) { return v; }
				}
				var capability = new PromiseCapability(C);
				var resolve = capability.resolve;
				resolve(v); // call with this===undefined
				return capability.promise;
			};

			Promise.prototype['catch'] = function( onRejected ) {
				return this.then(undefined, onRejected);
			};

			Promise.prototype.then = function( onFulfilled, onRejected ) {
				var promise = this;
				if (!ES.IsPromise(promise)) { throw new TypeError('not a promise'); }
				// this.constructor not this._promiseConstructor; see
				// https://bugs.ecmascript.org/show_bug.cgi?id=2513
				var C = this.constructor;
				var capability = new PromiseCapability(C);
				if (!ES.IsCallable(onRejected)) {
					onRejected = function(e) { throw e; };
				}
				if (!ES.IsCallable(onFulfilled)) {
					onFulfilled = function(x) { return x; };
				}
				var resolutionHandler =
					promiseResolutionHandler(promise, onFulfilled, onRejected);
				var resolveReaction =
				{ capability: capability, handler: resolutionHandler };
				var rejectReaction =
				{ capability: capability, handler: onRejected };
				switch (promise._status) {
					case 'unresolved':
						promise._resolveReactions.push(resolveReaction);
						promise._rejectReactions.push(rejectReaction);
						break;
					case 'has-resolution':
						triggerPromiseReactions([resolveReaction], promise._result);
						break;
					case 'has-rejection':
						triggerPromiseReactions([rejectReaction], promise._result);
						break;
					default:
						throw new TypeError('unexpected');
				}
				return capability.promise;
			};

			return Promise;
		})();
		// export the Promise constructor.
		defineProperties(globals, { Promise: PromiseShim });
		// In Chrome 33 (and thereabouts) Promise is defined, but the
		// implementation is buggy in a number of ways.  Let's check subclassing
		// support to see if we have a buggy implementation.
		var promiseSupportsSubclassing = supportsSubclassing(globals.Promise, function(S) {
			return S.resolve(42) instanceof S;
		});
		var promiseIgnoresNonFunctionThenCallbacks = (function () {
			try {
				globals.Promise.reject(42).then(null, 5).then(null, function () {});
				return true;
			} catch (ex) {
				return false;
			}
		}());
		if (!promiseSupportsSubclassing || !promiseIgnoresNonFunctionThenCallbacks) {
			globals.Promise = PromiseShim;
		}

		// Map and Set require a true ES5 environment
		if (supportsDescriptors) {

			var fastkey = function fastkey(key) {
				var type = typeof key;
				if (type === 'string') {
					return '$' + key;
				} else if (type === 'number') {
					// note that -0 will get coerced to "0" when used as a property key
					return key;
				}
				return null;
			};

			var emptyObject = function emptyObject() {
				// accomodate some older not-quite-ES5 browsers
				return Object.create ? Object.create(null) : {};
			};

			var collectionShims = {
				Map: (function() {

					var empty = {};

					function MapEntry(key, value) {
						this.key = key;
						this.value = value;
						this.next = null;
						this.prev = null;
					}

					MapEntry.prototype.isRemoved = function() {
						return this.key === empty;
					};

					function MapIterator(map, kind) {
						this.head = map._head;
						this.i = this.head;
						this.kind = kind;
					}

					MapIterator.prototype = {
						next: function() {
							var i = this.i, kind = this.kind, head = this.head, result;
							if (this.i === undefined) {
								return { value: undefined, done: true };
							}
							while (i.isRemoved() && i !== head) {
								// back up off of removed entries
								i = i.prev;
							}
							// advance to next unreturned element.
							while (i.next !== head) {
								i = i.next;
								if (!i.isRemoved()) {
									if (kind === "key") {
										result = i.key;
									} else if (kind === "value") {
										result = i.value;
									} else {
										result = [i.key, i.value];
									}
									this.i = i;
									return { value: result, done: false };
								}
							}
							// once the iterator is done, it is done forever.
							this.i = undefined;
							return { value: undefined, done: true };
						}
					};
					addIterator(MapIterator.prototype);

					function Map() {
						var map = this;
						map = emulateES6construct(map);
						if (!map._es6map) {
							throw new TypeError('bad map');
						}

						var head = new MapEntry(null, null);
						// circular doubly-linked list.
						head.next = head.prev = head;

						defineProperties(map, {
							'_head': head,
							'_storage': emptyObject(),
							'_size': 0
						});

						// Optionally initialize map from iterable
						var iterable = arguments[0];
						if (iterable !== undefined && iterable !== null) {
							var it = ES.GetIterator(iterable);
							var adder = map.set;
							if (!ES.IsCallable(adder)) { throw new TypeError('bad map'); }
							while (true) {
								var next = ES.IteratorNext(it);
								if (next.done) { break; }
								var nextItem = next.value;
								if (!ES.TypeIsObject(nextItem)) {
									throw new TypeError('expected iterable of pairs');
								}
								adder.call(map, nextItem[0], nextItem[1]);
							}
						}
						return map;
					}
					var Map$prototype = Map.prototype;
					defineProperties(Map, {
						'@@create': function(obj) {
							var constructor = this;
							var prototype = constructor.prototype || Map$prototype;
							obj = obj || create(prototype);
							defineProperties(obj, { _es6map: true });
							return obj;
						}
					});

					Object.defineProperty(Map.prototype, 'size', {
						configurable: true,
						enumerable: false,
						get: function() {
							if (typeof this._size === 'undefined') {
								throw new TypeError('size method called on incompatible Map');
							}
							return this._size;
						}
					});

					defineProperties(Map.prototype, {
						get: function(key) {
							var fkey = fastkey(key);
							if (fkey !== null) {
								// fast O(1) path
								var entry = this._storage[fkey];
								return entry ? entry.value : undefined;
							}
							var head = this._head, i = head;
							while ((i = i.next) !== head) {
								if (ES.SameValueZero(i.key, key)) {
									return i.value;
								}
							}
							return undefined;
						},

						has: function(key) {
							var fkey = fastkey(key);
							if (fkey !== null) {
								// fast O(1) path
								return typeof this._storage[fkey] !== 'undefined';
							}
							var head = this._head, i = head;
							while ((i = i.next) !== head) {
								if (ES.SameValueZero(i.key, key)) {
									return true;
								}
							}
							return false;
						},

						set: function(key, value) {
							var head = this._head, i = head, entry;
							var fkey = fastkey(key);
							if (fkey !== null) {
								// fast O(1) path
								if (typeof this._storage[fkey] !== 'undefined') {
									this._storage[fkey].value = value;
									return;
								} else {
									entry = this._storage[fkey] = new MapEntry(key, value);
									i = head.prev;
									// fall through
								}
							}
							while ((i = i.next) !== head) {
								if (ES.SameValueZero(i.key, key)) {
									i.value = value;
									return;
								}
							}
							entry = entry || new MapEntry(key, value);
							if (ES.SameValue(-0, key)) {
								entry.key = +0; // coerce -0 to +0 in entry
							}
							entry.next = this._head;
							entry.prev = this._head.prev;
							entry.prev.next = entry;
							entry.next.prev = entry;
							this._size += 1;
						},

						'delete': function(key) {
							var head = this._head, i = head;
							var fkey = fastkey(key);
							if (fkey !== null) {
								// fast O(1) path
								if (typeof this._storage[fkey] === 'undefined') {
									return false;
								}
								i = this._storage[fkey].prev;
								delete this._storage[fkey];
								// fall through
							}
							while ((i = i.next) !== head) {
								if (ES.SameValueZero(i.key, key)) {
									i.key = i.value = empty;
									i.prev.next = i.next;
									i.next.prev = i.prev;
									this._size -= 1;
									return true;
								}
							}
							return false;
						},

						clear: function() {
							this._size = 0;
							this._storage = emptyObject();
							var head = this._head, i = head, p = i.next;
							while ((i = p) !== head) {
								i.key = i.value = empty;
								p = i.next;
								i.next = i.prev = head;
							}
							head.next = head.prev = head;
						},

						keys: function() {
							return new MapIterator(this, "key");
						},

						values: function() {
							return new MapIterator(this, "value");
						},

						entries: function() {
							return new MapIterator(this, "key+value");
						},

						forEach: function(callback) {
							var context = arguments.length > 1 ? arguments[1] : null;
							var it = this.entries();
							for (var entry = it.next(); !entry.done; entry = it.next()) {
								callback.call(context, entry.value[1], entry.value[0], this);
							}
						}
					});
					addIterator(Map.prototype, function() { return this.entries(); });

					return Map;
				})(),

				Set: (function() {
					// Creating a Map is expensive.  To speed up the common case of
					// Sets containing only string or numeric keys, we use an object
					// as backing storage and lazily create a full Map only when
					// required.
					var SetShim = function Set() {
						var set = this;
						set = emulateES6construct(set);
						if (!set._es6set) {
							throw new TypeError('bad set');
						}

						defineProperties(set, {
							'[[SetData]]': null,
							'_storage': emptyObject()
						});

						// Optionally initialize map from iterable
						var iterable = arguments[0];
						if (iterable !== undefined && iterable !== null) {
							var it = ES.GetIterator(iterable);
							var adder = set.add;
							if (!ES.IsCallable(adder)) { throw new TypeError('bad set'); }
							while (true) {
								var next = ES.IteratorNext(it);
								if (next.done) { break; }
								var nextItem = next.value;
								adder.call(set, nextItem);
							}
						}
						return set;
					};
					var Set$prototype = SetShim.prototype;
					defineProperties(SetShim, {
						'@@create': function(obj) {
							var constructor = this;
							var prototype = constructor.prototype || Set$prototype;
							obj = obj || create(prototype);
							defineProperties(obj, { _es6set: true });
							return obj;
						}
					});

					// Switch from the object backing storage to a full Map.
					var ensureMap = function ensureMap(set) {
						if (!set['[[SetData]]']) {
							var m = set['[[SetData]]'] = new collectionShims.Map();
							Object.keys(set._storage).forEach(function(k) {
								// fast check for leading '$'
								if (k.charCodeAt(0) === 36) {
									k = k.substring(1);
								} else {
									k = +k;
								}
								m.set(k, k);
							});
							set._storage = null; // free old backing storage
						}
					};

					Object.defineProperty(SetShim.prototype, 'size', {
						configurable: true,
						enumerable: false,
						get: function() {
							if (typeof this._storage === 'undefined') {
								// https://github.com/paulmillr/es6-shim/issues/176
								throw new TypeError('size method called on incompatible Set');
							}
							ensureMap(this);
							return this['[[SetData]]'].size;
						}
					});

					defineProperties(SetShim.prototype, {
						has: function(key) {
							var fkey;
							if (this._storage && (fkey = fastkey(key)) !== null) {
								return !!this._storage[fkey];
							}
							ensureMap(this);
							return this['[[SetData]]'].has(key);
						},

						add: function(key) {
							var fkey;
							if (this._storage && (fkey = fastkey(key)) !== null) {
								this._storage[fkey]=true;
								return;
							}
							ensureMap(this);
							return this['[[SetData]]'].set(key, key);
						},

						'delete': function(key) {
							var fkey;
							if (this._storage && (fkey = fastkey(key)) !== null) {
								delete this._storage[fkey];
								return;
							}
							ensureMap(this);
							return this['[[SetData]]']['delete'](key);
						},

						clear: function() {
							if (this._storage) {
								this._storage = emptyObject();
								return;
							}
							return this['[[SetData]]'].clear();
						},

						keys: function() {
							ensureMap(this);
							return this['[[SetData]]'].keys();
						},

						values: function() {
							ensureMap(this);
							return this['[[SetData]]'].values();
						},

						entries: function() {
							ensureMap(this);
							return this['[[SetData]]'].entries();
						},

						forEach: function(callback) {
							var context = arguments.length > 1 ? arguments[1] : null;
							var entireSet = this;
							ensureMap(this);
							this['[[SetData]]'].forEach(function(value, key) {
								callback.call(context, key, key, entireSet);
							});
						}
					});
					addIterator(SetShim.prototype, function() { return this.values(); });

					return SetShim;
				})()
			};
			defineProperties(globals, collectionShims);

			if (globals.Map || globals.Set) {
				/*
				 - In Firefox < 23, Map#size is a function.
				 - In all current Firefox, Set#entries/keys/values & Map#clear do not exist
				 - https://bugzilla.mozilla.org/show_bug.cgi?id=869996
				 - In Firefox 24, Map and Set do not implement forEach
				 - In Firefox 25 at least, Map and Set are callable without "new"
				 */
				if (
					typeof globals.Map.prototype.clear !== 'function' ||
						new globals.Set().size !== 0 ||
						new globals.Map().size !== 0 ||
						typeof globals.Map.prototype.keys !== 'function' ||
						typeof globals.Set.prototype.keys !== 'function' ||
						typeof globals.Map.prototype.forEach !== 'function' ||
						typeof globals.Set.prototype.forEach !== 'function' ||
						isCallableWithoutNew(globals.Map) ||
						isCallableWithoutNew(globals.Set) ||
						!supportsSubclassing(globals.Map, function(M) {
							return (new M([])) instanceof M;
						})
					) {
					globals.Map = collectionShims.Map;
					globals.Set = collectionShims.Set;
				}
			}
			// Shim incomplete iterator implementations.
			addIterator(Object.getPrototypeOf((new globals.Map()).keys()));
			addIterator(Object.getPrototypeOf((new globals.Set()).keys()));
		}
	};

	if (typeof define === 'function' && define.amd) {
		define(main); // RequireJS
	} else {
		main(); // CommonJS and <script>
	}
});