(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? factory() :
	typeof define === 'function' && define.amd ? define(factory) :
	(factory());
}(this, (function () { 'use strict';

/**
 * @this {Promise}
 */
function finallyConstructor(callback) {
  var constructor = this.constructor;
  return this.then(
    function(value) {
      return constructor.resolve(callback()).then(function() {
        return value;
      });
    },
    function(reason) {
      return constructor.resolve(callback()).then(function() {
        return constructor.reject(reason);
      });
    }
  );
}

// Store setTimeout reference so promise-polyfill will be unaffected by
// other code modifying setTimeout (like sinon.useFakeTimers())
var setTimeoutFunc = setTimeout;

function noop() {}

// Polyfill for Function.prototype.bind
function bind(fn, thisArg) {
  return function() {
    fn.apply(thisArg, arguments);
  };
}

/**
 * @constructor
 * @param {Function} fn
 */
function Promise(fn) {
  if (!(this instanceof Promise))
    throw new TypeError('Promises must be constructed via new');
  if (typeof fn !== 'function') throw new TypeError('not a function');
  /** @type {!number} */
  this._state = 0;
  /** @type {!boolean} */
  this._handled = false;
  /** @type {Promise|undefined} */
  this._value = undefined;
  /** @type {!Array<!Function>} */
  this._deferreds = [];

  doResolve(fn, this);
}

function handle(self, deferred) {
  while (self._state === 3) {
    self = self._value;
  }
  if (self._state === 0) {
    self._deferreds.push(deferred);
    return;
  }
  self._handled = true;
  Promise._immediateFn(function() {
    var cb = self._state === 1 ? deferred.onFulfilled : deferred.onRejected;
    if (cb === null) {
      (self._state === 1 ? resolve : reject)(deferred.promise, self._value);
      return;
    }
    var ret;
    try {
      ret = cb(self._value);
    } catch (e) {
      reject(deferred.promise, e);
      return;
    }
    resolve(deferred.promise, ret);
  });
}

function resolve(self, newValue) {
  try {
    // Promise Resolution Procedure: https://github.com/promises-aplus/promises-spec#the-promise-resolution-procedure
    if (newValue === self)
      throw new TypeError('A promise cannot be resolved with itself.');
    if (
      newValue &&
      (typeof newValue === 'object' || typeof newValue === 'function')
    ) {
      var then = newValue.then;
      if (newValue instanceof Promise) {
        self._state = 3;
        self._value = newValue;
        finale(self);
        return;
      } else if (typeof then === 'function') {
        doResolve(bind(then, newValue), self);
        return;
      }
    }
    self._state = 1;
    self._value = newValue;
    finale(self);
  } catch (e) {
    reject(self, e);
  }
}

function reject(self, newValue) {
  self._state = 2;
  self._value = newValue;
  finale(self);
}

function finale(self) {
  if (self._state === 2 && self._deferreds.length === 0) {
    Promise._immediateFn(function() {
      if (!self._handled) {
        Promise._unhandledRejectionFn(self._value);
      }
    });
  }

  for (var i = 0, len = self._deferreds.length; i < len; i++) {
    handle(self, self._deferreds[i]);
  }
  self._deferreds = null;
}

/**
 * @constructor
 */
function Handler(onFulfilled, onRejected, promise) {
  this.onFulfilled = typeof onFulfilled === 'function' ? onFulfilled : null;
  this.onRejected = typeof onRejected === 'function' ? onRejected : null;
  this.promise = promise;
}

/**
 * Take a potentially misbehaving resolver function and make sure
 * onFulfilled and onRejected are only called once.
 *
 * Makes no guarantees about asynchrony.
 */
function doResolve(fn, self) {
  var done = false;
  try {
    fn(
      function(value) {
        if (done) return;
        done = true;
        resolve(self, value);
      },
      function(reason) {
        if (done) return;
        done = true;
        reject(self, reason);
      }
    );
  } catch (ex) {
    if (done) return;
    done = true;
    reject(self, ex);
  }
}

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

Promise.prototype.then = function(onFulfilled, onRejected) {
  // @ts-ignore
  var prom = new this.constructor(noop);

  handle(this, new Handler(onFulfilled, onRejected, prom));
  return prom;
};

Promise.prototype['finally'] = finallyConstructor;

Promise.all = function(arr) {
  return new Promise(function(resolve, reject) {
    if (!arr || typeof arr.length === 'undefined')
      throw new TypeError('Promise.all accepts an array');
    var args = Array.prototype.slice.call(arr);
    if (args.length === 0) return resolve([]);
    var remaining = args.length;

    function res(i, val) {
      try {
        if (val && (typeof val === 'object' || typeof val === 'function')) {
          var then = val.then;
          if (typeof then === 'function') {
            then.call(
              val,
              function(val) {
                res(i, val);
              },
              reject
            );
            return;
          }
        }
        args[i] = val;
        if (--remaining === 0) {
          resolve(args);
        }
      } catch (ex) {
        reject(ex);
      }
    }

    for (var i = 0; i < args.length; i++) {
      res(i, args[i]);
    }
  });
};

Promise.resolve = function(value) {
  if (value && typeof value === 'object' && value.constructor === Promise) {
    return value;
  }

  return new Promise(function(resolve) {
    resolve(value);
  });
};

Promise.reject = function(value) {
  return new Promise(function(resolve, reject) {
    reject(value);
  });
};

Promise.race = function(values) {
  return new Promise(function(resolve, reject) {
    for (var i = 0, len = values.length; i < len; i++) {
      values[i].then(resolve, reject);
    }
  });
};

// Use polyfill for setImmediate for performance gains
Promise._immediateFn =
  (typeof setImmediate === 'function' &&
    function(fn) {
      setImmediate(fn);
    }) ||
  function(fn) {
    setTimeoutFunc(fn, 0);
  };

Promise._unhandledRejectionFn = function _unhandledRejectionFn(err) {
  if (typeof console !== 'undefined' && console) {
    console.warn('Possible Unhandled Promise Rejection:', err); // eslint-disable-line no-console
  }
};

/** @suppress {undefinedVars} */
var globalNS = (function() {
  // the only reliable means to get the global object is
  // `Function('return this')()`
  // However, this causes CSP violations in Chrome apps.
  if (typeof self !== 'undefined') {
    return self;
  }
  if (typeof window !== 'undefined') {
    return window;
  }
  if (typeof global !== 'undefined') {
    return global;
  }
  throw new Error('unable to locate global object');
})();

if (!('Promise' in globalNS)) {
  globalNS['Promise'] = Promise;
} else if (!globalNS.Promise.prototype['finally']) {
  globalNS.Promise.prototype['finally'] = finallyConstructor;
}

})));
/* global Symbol */
// URL Polyfill
// Draft specification: https://url.spec.whatwg.org

// Notes:
// - Primarily useful for parsing URLs and modifying query parameters
// - Should work in IE8+ and everything more modern, with es5.js polyfills

(function (global) {
  'use strict';

  function isSequence(o) {
    if (!o) return false;
    if ('Symbol' in global && 'iterator' in global.Symbol &&
        typeof o[Symbol.iterator] === 'function') return true;
    if (Array.isArray(o)) return true;
    return false;
  }

  function toArray(iter) {
    return ('from' in Array) ? Array.from(iter) : Array.prototype.slice.call(iter);
  }

  (function() {

    // Browsers may have:
    // * No global URL object
    // * URL with static methods only - may have a dummy constructor
    // * URL with members except searchParams
    // * Full URL API support
    var origURL = global.URL;
    var nativeURL;
    try {
      if (origURL) {
        nativeURL = new global.URL('http://example.com');
        if ('searchParams' in nativeURL) {
					var url = new URL('http://example.com');
					url.search = 'a=1&b=2';
					if (url.href === 'http://example.com/?a=1&b=2') {
						url.search = '';
						if (url.href === 'http://example.com/') {
							return;
						}
					}
				}
        if (!('href' in nativeURL)) {
					nativeURL = undefined;
				}
				nativeURL = undefined;
      }
    } catch (_) {}

    // NOTE: Doesn't do the encoding/decoding dance
    function urlencoded_serialize(pairs) {
      var output = '', first = true;
      pairs.forEach(function (pair) {
        var name = encodeURIComponent(pair.name);
        var value = encodeURIComponent(pair.value);
        if (!first) output += '&';
        output += name + '=' + value;
        first = false;
      });
      return output.replace(/%20/g, '+');
    }

    // NOTE: Doesn't do the encoding/decoding dance
    function urlencoded_parse(input, isindex) {
      var sequences = input.split('&');
      if (isindex && sequences[0].indexOf('=') === -1)
        sequences[0] = '=' + sequences[0];
      var pairs = [];
      sequences.forEach(function (bytes) {
        if (bytes.length === 0) return;
        var index = bytes.indexOf('=');
        if (index !== -1) {
          var name = bytes.substring(0, index);
          var value = bytes.substring(index + 1);
        } else {
          name = bytes;
          value = '';
        }
        name = name.replace(/\+/g, ' ');
        value = value.replace(/\+/g, ' ');
        pairs.push({ name: name, value: value });
      });
      var output = [];
      pairs.forEach(function (pair) {
        output.push({
          name: decodeURIComponent(pair.name),
          value: decodeURIComponent(pair.value)
        });
      });
      return output;
    }

    function URLUtils(url) {
      if (nativeURL)
        return new origURL(url);
      var anchor = document.createElement('a');
      anchor.href = url;
      return anchor;
    }

    function URLSearchParams(init) {
      var $this = this;
      this._list = [];

      if (init === undefined || init === null) {
        // no-op
      } else if (init instanceof URLSearchParams) {
        // In ES6 init would be a sequence, but special case for ES5.
        this._list = urlencoded_parse(String(init));
      } else if (typeof init === 'object' && isSequence(init)) {
        toArray(init).forEach(function(e) {
          if (!isSequence(e)) throw TypeError();
          var nv = toArray(e);
          if (nv.length !== 2) throw TypeError();
          $this._list.push({name: String(nv[0]), value: String(nv[1])});
        });
      } else if (typeof init === 'object' && init) {
        Object.keys(init).forEach(function(key) {
          $this._list.push({name: String(key), value: String(init[key])});
        });
      } else {
        init = String(init);
        if (init.substring(0, 1) === '?')
          init = init.substring(1);
        this._list = urlencoded_parse(init);
      }

      this._url_object = null;
      this._setList = function (list) { if (!updating) $this._list = list; };

      var updating = false;
      this._update_steps = function() {
        if (updating) return;
        updating = true;

        if (!$this._url_object) return;

        // Partial workaround for IE issue with 'about:'
        if ($this._url_object.protocol === 'about:' &&
            $this._url_object.pathname.indexOf('?') !== -1) {
          $this._url_object.pathname = $this._url_object.pathname.split('?')[0];
        }

        $this._url_object.search = urlencoded_serialize($this._list);

        updating = false;
      };
    }


    Object.defineProperties(URLSearchParams.prototype, {
      append: {
        value: function (name, value) {
          this._list.push({ name: name, value: value });
          this._update_steps();
        }, writable: true, enumerable: true, configurable: true
      },

      'delete': {
        value: function (name) {
          for (var i = 0; i < this._list.length;) {
            if (this._list[i].name === name)
              this._list.splice(i, 1);
            else
              ++i;
          }
          this._update_steps();
        }, writable: true, enumerable: true, configurable: true
      },

      get: {
        value: function (name) {
          for (var i = 0; i < this._list.length; ++i) {
            if (this._list[i].name === name)
              return this._list[i].value;
          }
          return null;
        }, writable: true, enumerable: true, configurable: true
      },

      getAll: {
        value: function (name) {
          var result = [];
          for (var i = 0; i < this._list.length; ++i) {
            if (this._list[i].name === name)
              result.push(this._list[i].value);
          }
          return result;
        }, writable: true, enumerable: true, configurable: true
      },

      has: {
        value: function (name) {
          for (var i = 0; i < this._list.length; ++i) {
            if (this._list[i].name === name)
              return true;
          }
          return false;
        }, writable: true, enumerable: true, configurable: true
      },

      set: {
        value: function (name, value) {
          var found = false;
          for (var i = 0; i < this._list.length;) {
            if (this._list[i].name === name) {
              if (!found) {
                this._list[i].value = value;
                found = true;
                ++i;
              } else {
                this._list.splice(i, 1);
              }
            } else {
              ++i;
            }
          }

          if (!found)
            this._list.push({ name: name, value: value });

          this._update_steps();
        }, writable: true, enumerable: true, configurable: true
      },

      entries: {
        value: function() { return new Iterator(this._list, 'key+value'); },
        writable: true, enumerable: true, configurable: true
      },

      keys: {
        value: function() { return new Iterator(this._list, 'key'); },
        writable: true, enumerable: true, configurable: true
      },

      values: {
        value: function() { return new Iterator(this._list, 'value'); },
        writable: true, enumerable: true, configurable: true
      },

      forEach: {
        value: function(callback) {
          var thisArg = (arguments.length > 1) ? arguments[1] : undefined;
          this._list.forEach(function(pair) {
            callback.call(thisArg, pair.value, pair.name);
          });

        }, writable: true, enumerable: true, configurable: true
      },

      toString: {
        value: function () {
          return urlencoded_serialize(this._list);
        }, writable: true, enumerable: false, configurable: true
      }
    });

    function Iterator(source, kind) {
      var index = 0;
      this['next'] = function() {
        if (index >= source.length)
          return {done: true, value: undefined};
        var pair = source[index++];
        return {done: false, value:
                kind === 'key' ? pair.name :
                kind === 'value' ? pair.value :
                [pair.name, pair.value]};
      };
    }

    if ('Symbol' in global && 'iterator' in global.Symbol) {
      Object.defineProperty(URLSearchParams.prototype, global.Symbol.iterator, {
        value: URLSearchParams.prototype.entries,
        writable: true, enumerable: true, configurable: true});
      Object.defineProperty(Iterator.prototype, global.Symbol.iterator, {
        value: function() { return this; },
        writable: true, enumerable: true, configurable: true});
    }

    function URL(url, base) {
      if (!(this instanceof global.URL))
        throw new TypeError("Failed to construct 'URL': Please use the 'new' operator.");

      if (base) {
        url = (function () {
          if (nativeURL) return new origURL(url, base).href;
          var iframe;
          try {
            var doc;
            // Use another document/base tag/anchor for relative URL resolution, if possible
            if (Object.prototype.toString.call(window.operamini) === "[object OperaMini]") {
              iframe = document.createElement('iframe');
              iframe.style.display = 'none';
              document.documentElement.appendChild(iframe);
              doc = iframe.contentWindow.document;
            } else if (document.implementation && document.implementation.createHTMLDocument) {
              doc = document.implementation.createHTMLDocument('');
            } else if (document.implementation && document.implementation.createDocument) {
              doc = document.implementation.createDocument('http://www.w3.org/1999/xhtml', 'html', null);
              doc.documentElement.appendChild(doc.createElement('head'));
              doc.documentElement.appendChild(doc.createElement('body'));
            } else if (window.ActiveXObject) {
              doc = new window.ActiveXObject('htmlfile');
              doc.write('<head><\/head><body><\/body>');
              doc.close();
            }

            if (!doc) throw Error('base not supported');

            var baseTag = doc.createElement('base');
            baseTag.href = base;
            doc.getElementsByTagName('head')[0].appendChild(baseTag);
            var anchor = doc.createElement('a');
            anchor.href = url;
            return anchor.href;
          } finally {
            if (iframe)
              iframe.parentNode.removeChild(iframe);
          }
        }());
      }

      // An inner object implementing URLUtils (either a native URL
      // object or an HTMLAnchorElement instance) is used to perform the
      // URL algorithms. With full ES5 getter/setter support, return a
      // regular object For IE8's limited getter/setter support, a
      // different HTMLAnchorElement is returned with properties
      // overridden

      var instance = URLUtils(url || '');

      // Detect for ES5 getter/setter support
      // (an Object.defineProperties polyfill that doesn't support getters/setters may throw)
      var ES5_GET_SET = (function() {
        if (!('defineProperties' in Object)) return false;
        try {
          var obj = {};
          Object.defineProperties(obj, { prop: { 'get': function () { return true; } } });
          return obj.prop;
        } catch (_) {
          return false;
        }
      }());

      var self = ES5_GET_SET ? this : document.createElement('a');



      var query_object = new URLSearchParams(
        instance.search ? instance.search.substring(1) : null);
      query_object._url_object = self;

      Object.defineProperties(self, {
        href: {
          get: function () { return instance.href; },
          set: function (v) { instance.href = v; tidy_instance(); update_steps(); },
          enumerable: true, configurable: true
        },
        origin: {
          get: function () {
            if ('origin' in instance) return instance.origin;
            return this.protocol + '//' + this.host;
          },
          enumerable: true, configurable: true
        },
        protocol: {
          get: function () { return instance.protocol; },
          set: function (v) { instance.protocol = v; },
          enumerable: true, configurable: true
        },
        username: {
          get: function () { return instance.username; },
          set: function (v) { instance.username = v; },
          enumerable: true, configurable: true
        },
        password: {
          get: function () { return instance.password; },
          set: function (v) { instance.password = v; },
          enumerable: true, configurable: true
        },
        host: {
          get: function () {
            // IE returns default port in |host|
            var re = {'http:': /:80$/, 'https:': /:443$/, 'ftp:': /:21$/}[instance.protocol];
            return re ? instance.host.replace(re, '') : instance.host;
          },
          set: function (v) { instance.host = v; },
          enumerable: true, configurable: true
        },
        hostname: {
          get: function () { return instance.hostname; },
          set: function (v) { instance.hostname = v; },
          enumerable: true, configurable: true
        },
        port: {
          get: function () { return instance.port; },
          set: function (v) { instance.port = v; },
          enumerable: true, configurable: true
        },
        pathname: {
          get: function () {
            // IE does not include leading '/' in |pathname|
            if (instance.pathname.charAt(0) !== '/') return '/' + instance.pathname;
            return instance.pathname;
          },
          set: function (v) { instance.pathname = v; },
          enumerable: true, configurable: true
        },
        search: {
          get: function () { return instance.search; },
          set: function (v) {
            if (instance.search === v) return;
            instance.search = v; tidy_instance(); update_steps();
          },
          enumerable: true, configurable: true
        },
        searchParams: {
          get: function () { return query_object; },
          enumerable: true, configurable: true
        },
        hash: {
          get: function () { return instance.hash; },
          set: function (v) { instance.hash = v; tidy_instance(); },
          enumerable: true, configurable: true
        },
        toString: {
          value: function() { return instance.toString(); },
          enumerable: false, configurable: true
        },
        valueOf: {
          value: function() { return instance.valueOf(); },
          enumerable: false, configurable: true
        }
      });

      function tidy_instance() {
        var href = instance.href.replace(/#$|\?$|\?(?=#)/g, '');
        if (instance.href !== href)
          instance.href = href;
      }

      function update_steps() {
        query_object._setList(instance.search ? urlencoded_parse(instance.search.substring(1)) : []);
        query_object._update_steps();
      }

      return self;
    }

    if (origURL) {
      for (var i in origURL) {
        if (origURL.hasOwnProperty(i) && typeof origURL[i] === 'function')
          URL[i] = origURL[i];
      }
    }

    global.URL = URL;
    global.URLSearchParams = URLSearchParams;
  }());

  // Patch native URLSearchParams constructor to handle sequences/records
  // if necessary.
  (function() {
    if (new global.URLSearchParams([['a', 1]]).get('a') === '1' &&
        new global.URLSearchParams({a: 1}).get('a') === '1')
      return;
    var orig = global.URLSearchParams;
    global.URLSearchParams = function(init) {
      if (init && typeof init === 'object' && isSequence(init)) {
        var o = new orig();
        toArray(init).forEach(function(e) {
          if (!isSequence(e)) throw TypeError();
          var nv = toArray(e);
          if (nv.length !== 2) throw TypeError();
          o.append(nv[0], nv[1]);
        });
        return o;
      } else if (init && typeof init === 'object') {
        o = new orig();
        Object.keys(init).forEach(function(key) {
          o.set(key, init[key]);
        });
        return o;
      } else {
        return new orig(init);
      }
    };
  }());

}(self));
// Array.includes
if (!Array.prototype.includes) {
	Object.defineProperty(Array.prototype, 'includes', {
		value: function(searchElement, fromIndex) {

			// 1. Let O be ? ToObject(this value).
			if (this == null) {
				throw new TypeError('"this" is null or not defined');
			}

			var o = Object(this);

			// 2. Let len be ? ToLength(? Get(O, "length")).
			var len = o.length >>> 0;

			// 3. If len is 0, return false.
			if (len === 0) {
				return false;
			}

			// 4. Let n be ? ToInteger(fromIndex).
			//    (If fromIndex is undefined, this step produces the value 0.)
			var n = fromIndex | 0;

			// 5. If n ??0, then
			//  a. Let k be n.
			// 6. Else n < 0,
			//  a. Let k be len + n.
			//  b. If k < 0, let k be 0.
			var k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);

			function sameValueZero(x, y) {
				return x === y || (typeof x === 'number' && typeof y === 'number' && isNaN(x) && isNaN(y));
			}

			// 7. Repeat, while k < len
			while (k < len) {
				// a. Let elementK be the result of ? Get(O, ! ToString(k)).
				// b. If SameValueZero(searchElement, elementK) is true, return true.
				// c. Increase k by 1. 
				if (sameValueZero(o[k], searchElement)) {
				return true;
				}
				k++;
			}

			// 8. Return false
			return false;
		}
	});
}// String.includes
if (!String.prototype.includes) {
	String.prototype.includes = function(search, start) {
		'use strict';
		if (typeof start !== 'number') {
			start = 0;
		}
		
		if (start + search.length > this.length) {
			return false;
		} else {
			return this.indexOf(search, start) !== -1;
		}
	};
}

if (!String.prototype.startsWith) {
	String.prototype.startsWith = function(searchString, position) {
		return this.substr(position || 0, searchString.length) === searchString;
	};
}

if (!String.prototype.endsWith) {
	String.prototype.endsWith = function(searchStr, Position) {
		// This works much better than >= because
		// it compensates for NaN:
		if (!(Position < this.length))
			Position = this.length;
		else
			Position |= 0; // round position
		return this.substr(Position - searchStr.length, searchStr.length) === searchStr;
	};
}if (typeof Object.assign !== 'function') {
	// Must be writable: true, enumerable: false, configurable: true
	Object.defineProperty(Object, "assign", {
		value: function assign(target, varArgs) { // .length of function is 2
			'use strict';
			if (target === null || target === undefined) {
				throw new TypeError('Cannot convert undefined or null to object');
			}

			var to = Object(target);

			for (var index = 1; index < arguments.length; index++) {
				var nextSource = arguments[index];

				if (nextSource !== null && nextSource !== undefined) { 
					for (var nextKey in nextSource) {
						// Avoid bugs when hasOwnProperty is shadowed
						if (Object.prototype.hasOwnProperty.call(nextSource, nextKey)) {
							to[nextKey] = nextSource[nextKey];
						}
					}
				}
			}
			return to;
		},
		writable: true,
		configurable: true
	});
}(function (global) {
	var rafPrefix;

	// do not inject RAF in order to avoid broken performance
	var nowOffset = Date.now();

	// use performance api if exist, otherwise use Date.now.
	// Date.now polyfill required.
	var pnow = function () {
		if (global.performance && typeof global.performance.now === 'function') {
			return global.performance.now();
		}
		// fallback
		return Date.now() - nowOffset;
	};

	if ('mozRequestAnimationFrame' in global) {
		rafPrefix = 'moz';

	} else if ('webkitRequestAnimationFrame' in global) {
		rafPrefix = 'webkit';

	}

	if (rafPrefix) {
		if (!global.requestAnimationFrame) //***
			global.requestAnimationFrame = function (callback) {
				return global[rafPrefix + 'RequestAnimationFrame'](function () {
					callback(pnow());
				});
			};
		if (!global.cancelAnimationFrame) //***
			global.cancelAnimationFrame = global[rafPrefix + 'CancelAnimationFrame'];
	} else {

		var lastTime = Date.now();

		global.requestAnimationFrame = function (callback) {
			if (typeof callback !== 'function') {
				throw new TypeError(callback + ' is not a function');
			}

			var
			currentTime = Date.now(),
			delay = 16 + lastTime - currentTime;

			if (delay < 0) {
				delay = 0;
			}

			lastTime = currentTime;

			return setTimeout(function () {
				lastTime = Date.now();

				callback(pnow());
			}, delay);
		};

		global.cancelAnimationFrame = function (id) {
			clearTimeout(id);
		};
	}
}(this));
/* global FormData self Blob File */
/* eslint-disable no-inner-declarations */

if (typeof Blob !== 'undefined' && (typeof FormData === 'undefined' || !FormData.prototype.keys)) {
  const global = typeof window === 'object'
    ? window
    : typeof self === 'object' ? self : this

  // keep a reference to native implementation
  const _FormData = global.FormData

  // To be monkey patched
  const _send = global.XMLHttpRequest && global.XMLHttpRequest.prototype.send
  const _fetch = global.Request && global.fetch
  const _sendBeacon = global.navigator && global.navigator.sendBeacon

  // Unable to patch Request constructor correctly
  // const _Request = global.Request
  // only way is to use ES6 class extend
  // https://github.com/babel/babel/issues/1966

  const stringTag = global.Symbol && Symbol.toStringTag

  // Add missing stringTags to blob and files
  if (stringTag) {
    if (!Blob.prototype[stringTag]) {
      Blob.prototype[stringTag] = 'Blob'
    }

    if ('File' in global && !File.prototype[stringTag]) {
      File.prototype[stringTag] = 'File'
    }
  }

  // Fix so you can construct your own File
  try {
    new File([], '') // eslint-disable-line
  } catch (a) {
    global.File = function File (b, d, c) {
      const blob = new Blob(b, c)
      const t = c && void 0 !== c.lastModified ? new Date(c.lastModified) : new Date()

      Object.defineProperties(blob, {
        name: {
          value: d
        },
        lastModifiedDate: {
          value: t
        },
        lastModified: {
          value: +t
        },
        toString: {
          value () {
            return '[object File]'
          }
        }
      })

      if (stringTag) {
        Object.defineProperty(blob, stringTag, {
          value: 'File'
        })
      }

      return blob
    }
  }

  function normalizeValue ([value, filename]) {
    if (value instanceof Blob) {
      // Should always returns a new File instance
      // console.assert(fd.get(x) !== fd.get(x))
      value = new File([value], filename, {
        type: value.type,
        lastModified: value.lastModified
      })
    }

    return value
  }

  function ensureArgs (args, expected) {
    if (args.length < expected) {
      throw new TypeError(`${expected} argument required, but only ${args.length} present.`)
    }
  }

  function normalizeArgs (name, value, filename) {
    return value instanceof Blob
      // normalize name and filename if adding an attachment
      ? [String(name), value, filename !== undefined
        ? filename + '' // Cast filename to string if 3th arg isn't undefined
        : typeof value.name === 'string' // if name prop exist
          ? value.name // Use File.name
          : 'blob'] // otherwise fallback to Blob

      // If no attachment, just cast the args to strings
      : [String(name), String(value)]
  }

  // normalize linefeeds for textareas
  // https://html.spec.whatwg.org/multipage/form-elements.html#textarea-line-break-normalisation-transformation
  function normalizeLinefeeds (value) {
    return value.replace(/\r\n/g, '\n').replace(/\n/g, '\r\n')
  }

  function each (arr, cb) {
    for (let i = 0; i < arr.length; i++) {
      cb(arr[i])
    }
  }

  /**
   * @implements {Iterable}
   */
  class FormDataPolyfill {
    /**
     * FormData class
     *
     * @param {HTMLElement=} form
     */
    constructor (form) {
      this._data = Object.create(null)

      if (!form) return this

      const self = this

      each(form.elements, elm => {
        if (!elm.name || elm.disabled || elm.type === 'submit' || elm.type === 'button') return

        if (elm.type === 'file') {
          const files = elm.files && elm.files.length
            ? elm.files
            : [new File([], '', { type: 'application/octet-stream' })] // #78

          each(files, file => {
            self.append(elm.name, file)
          })
        } else if (elm.type === 'select-multiple' || elm.type === 'select-one') {
          each(elm.options, opt => {
            !opt.disabled && opt.selected && self.append(elm.name, opt.value)
          })
        } else if (elm.type === 'checkbox' || elm.type === 'radio') {
          if (elm.checked) self.append(elm.name, elm.value)
        } else {
          const value = elm.type === 'textarea' ? normalizeLinefeeds(elm.value) : elm.value
          self.append(elm.name, value)
        }
      })
    }

    /**
     * Append a field
     *
     * @param   {string}           name      field name
     * @param   {string|Blob|File} value     string / blob / file
     * @param   {string=}          filename  filename to use with blob
     * @return  {undefined}
     */
    append (name, value, filename) {
      ensureArgs(arguments, 2)
      ;[name, value, filename] = normalizeArgs.apply(null, arguments)
      const map = this._data

      if (!map[name]) map[name] = []

      map[name].push([value, filename])
    }

    /**
     * Delete all fields values given name
     *
     * @param   {string}  name  Field name
     * @return  {undefined}
     */
    delete (name) {
      ensureArgs(arguments, 1)
      delete this._data[String(name)]
    }

    /**
     * Iterate over all fields as [name, value]
     *
     * @return {Iterator}
     */
    * entries () {
      const map = this._data

      for (const name in map) {
        for (const value of map[name]) {
          yield [name, normalizeValue(value)]
        }
      }
    }

    /**
     * Iterate over all fields
     *
     * @param   {Function}  callback  Executed for each item with parameters (value, name, thisArg)
     * @param   {Object=}   thisArg   `this` context for callback function
     * @return  {undefined}
     */
    forEach (callback, thisArg) {
      ensureArgs(arguments, 1)
      for (const [name, value] of this) {
        callback.call(thisArg, value, name, this)
      }
    }

    /**
     * Return first field value given name
     * or null if non existen
     *
     * @param   {string}  name      Field name
     * @return  {string|File|null}  value Fields value
     */
    get (name) {
      ensureArgs(arguments, 1)
      const map = this._data
      name = String(name)
      return map[name] ? normalizeValue(map[name][0]) : null
    }

    /**
     * Return all fields values given name
     *
     * @param   {string}  name  Fields name
     * @return  {Array}         [{String|File}]
     */
    getAll (name) {
      ensureArgs(arguments, 1)
      return (this._data[String(name)] || []).map(normalizeValue)
    }

    /**
     * Check for field name existence
     *
     * @param   {string}   name  Field name
     * @return  {boolean}
     */
    has (name) {
      ensureArgs(arguments, 1)
      return String(name) in this._data
    }

    /**
     * Iterate over all fields name
     *
     * @return {Iterator}
     */
    * keys () {
      for (const [name] of this) {
        yield name
      }
    }

    /**
     * Overwrite all values given name
     *
     * @param   {string}    name      Filed name
     * @param   {string}    value     Field value
     * @param   {string=}   filename  Filename (optional)
     * @return  {undefined}
     */
    set (name, value, filename) {
      ensureArgs(arguments, 2)
      const args = normalizeArgs.apply(null, arguments)
      this._data[args[0]] = [[args[1], args[2]]]
    }

    /**
     * Iterate over all fields
     *
     * @return {Iterator}
     */
    * values () {
      for (const [, value] of this) {
        yield value
      }
    }

    /**
     * Return a native (perhaps degraded) FormData with only a `append` method
     * Can throw if it's not supported
     *
     * @return {FormData}
     */
    ['_asNative'] () {
      const fd = new _FormData()

      for (const [name, value] of this) {
        fd.append(name, value)
      }

      return fd
    }

    /**
     * [_blob description]
     *
     * @return {Blob} [description]
     */
    ['_blob'] () {
      const boundary = '----formdata-polyfill-' + Math.random()
      const chunks = []

      for (const [name, value] of this) {
        chunks.push(`--${boundary}\r\n`)

        if (value instanceof Blob) {
          chunks.push(
            `Content-Disposition: form-data; name="${name}"; filename="${value.name}"\r\n`,
            `Content-Type: ${value.type || 'application/octet-stream'}\r\n\r\n`,
            value,
            '\r\n'
          )
        } else {
          chunks.push(
            `Content-Disposition: form-data; name="${name}"\r\n\r\n${value}\r\n`
          )
        }
      }

      chunks.push(`--${boundary}--`)

      return new Blob(chunks, {
        type: 'multipart/form-data; boundary=' + boundary
      })
    }

    /**
     * The class itself is iterable
     * alias for formdata.entries()
     *
     * @return  {Iterator}
     */
    [Symbol.iterator] () {
      return this.entries()
    }

    /**
     * Create the default string description.
     *
     * @return  {string} [object FormData]
     */
    toString () {
      return '[object FormData]'
    }
  }

  if (stringTag) {
    /**
     * Create the default string description.
     * It is accessed internally by the Object.prototype.toString().
     */
    FormDataPolyfill.prototype[stringTag] = 'FormData'
  }

  // Patch xhr's send method to call _blob transparently
  if (_send) {
    const setRequestHeader = global.XMLHttpRequest.prototype.setRequestHeader

    /**
     * @param {string} name
     * @param {string} value
     * @returns {undefined}
     * @see https://xhr.spec.whatwg.org/#dom-xmlhttprequest-setrequestheader
     */
    global.XMLHttpRequest.prototype.setRequestHeader = function (name, value) {
      setRequestHeader.call(this, name, value)
      if (name.toLowerCase() === 'content-type') this._hasContentType = true
    }

    /**
     * @param {ArrayBuffer|ArrayBufferView|Blob|Document|FormData|string=} data
     * @return {undefined}
     * @see https://xhr.spec.whatwg.org/#the-send()-method
     */
    global.XMLHttpRequest.prototype.send = function (data) {
      // need to patch send b/c old IE don't send blob's type (#44)
      if (data instanceof FormDataPolyfill) {
        const blob = data['_blob']()
        if (!this._hasContentType) this.setRequestHeader('Content-Type', blob.type)
        _send.call(this, blob)
      } else {
        _send.call(this, data)
      }
    }
  }

  // Patch fetch's function to call _blob transparently
  if (_fetch) {
    const _fetch = global.fetch

    global.fetch = function (input, init) {
      if (init && init.body && init.body instanceof FormDataPolyfill) {
        init.body = init.body['_blob']()
      }

      return _fetch.call(this, input, init)
    }
  }

  // Patch navigator.sendBeacon to use native FormData
  if (_sendBeacon) {
    global.navigator.sendBeacon = function (url, data) {
      if (data instanceof FormDataPolyfill) {
        data = data['_asNative']()
      }
      return _sendBeacon.call(this, url, data)
    }
  }

  global['FormData'] = FormDataPolyfill
}