(function (global, factory) {

typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
typeof define === 'function' && define.amd ? define(['exports'], factory) :
(factory((global.WHATWGFetch = {})));

}(this, (function (exports) { 'use strict';

var support = {
  searchParams: 'URLSearchParams' in self,
  iterable: 'Symbol' in self && 'iterator' in Symbol,
  blob:
    'FileReader' in self &&
    'Blob' in self &&
    (function() {
      try {
        new Blob();
        return true
      } catch (e) {
        return false
      }
    })(),
  formData: 'FormData' in self,
  arrayBuffer: 'ArrayBuffer' in self
};
function isDataView(obj) {
  return obj && DataView.prototype.isPrototypeOf(obj)
}
if (support.arrayBuffer) {
  var viewClasses = [
    '[object Int8Array]',
    '[object Uint8Array]',
    '[object Uint8ClampedArray]',
    '[object Int16Array]',
    '[object Uint16Array]',
    '[object Int32Array]',
    '[object Uint32Array]',
    '[object Float32Array]',
    '[object Float64Array]'
  ];
  var isArrayBufferView =
    ArrayBuffer.isView ||
    function(obj) {
      return obj && viewClasses.indexOf(Object.prototype.toString.call(obj)) > -1
    };
}
function normalizeName(name) {
  if (typeof name !== 'string') {
    name = String(name);
  }
  if (/[^a-z0-9\-#$%&'*+.^_`|~]/i.test(name)) {
    throw new TypeError('Invalid character in header field name')
  }
  return name.toLowerCase()
}
function normalizeValue(value) {
  if (typeof value !== 'string') {
    value = String(value);
  }
  return value
}
// Build a destructive iterator for the value list
function iteratorFor(items) {
  var iterator = {
    next: function() {
      var value = items.shift();
      return {done: value === undefined, value: value}
    }
  };
  if (support.iterable) {
    iterator[Symbol.iterator] = function() {
      return iterator
    };
  }
  return iterator
}
function Headers(headers) {
  this.map = {};
  if (headers instanceof Headers) {
    headers.forEach(function(value, name) {
      this.append(name, value);
    }, this);
  } else if (Array.isArray(headers)) {
    headers.forEach(function(header) {
      this.append(header[0], header[1]);
    }, this);
  } else if (headers) {
    Object.getOwnPropertyNames(headers).forEach(function(name) {
      this.append(name, headers[name]);
    }, this);
  }
}
Headers.prototype.append = function(name, value) {
  name = normalizeName(name);
  value = normalizeValue(value);
  var oldValue = this.map[name];
  this.map[name] = oldValue ? oldValue + ', ' + value : value;
};
Headers.prototype['delete'] = function(name) {
  delete this.map[normalizeName(name)];
};
Headers.prototype.get = function(name) {
  name = normalizeName(name);
  return this.has(name) ? this.map[name] : null
};
Headers.prototype.has = function(name) {
  return this.map.hasOwnProperty(normalizeName(name))
};
Headers.prototype.set = function(name, value) {
  this.map[normalizeName(name)] = normalizeValue(value);
};
Headers.prototype.forEach = function(callback, thisArg) {
  for (var name in this.map) {
    if (this.map.hasOwnProperty(name)) {
      callback.call(thisArg, this.map[name], name, this);
    }
  }
};
Headers.prototype.keys = function() {
  var items = [];
  this.forEach(function(value, name) {
    items.push(name);
  });
  return iteratorFor(items)
};
Headers.prototype.values = function() {
  var items = [];
  this.forEach(function(value) {
    items.push(value);
  });
  return iteratorFor(items)
};
Headers.prototype.entries = function() {
  var items = [];
  this.forEach(function(value, name) {
    items.push([name, value]);
  });
  return iteratorFor(items)
};
if (support.iterable) {
  Headers.prototype[Symbol.iterator] = Headers.prototype.entries;
}
function consumed(body) {
  if (body.bodyUsed) {
    return Promise.reject(new TypeError('Already read'))
  }
  body.bodyUsed = true;
}
function fileReaderReady(reader) {
  return new Promise(function(resolve, reject) {
    reader.onload = function() {
      resolve(reader.result);
    };
    reader.onerror = function() {
      reject(reader.error);
    };
  })
}
function readBlobAsArrayBuffer(blob) {
  var reader = new FileReader();
  var promise = fileReaderReady(reader);
  reader.readAsArrayBuffer(blob);
  return promise
}
function readBlobAsText(blob) {
  var reader = new FileReader();
  var promise = fileReaderReady(reader);
  reader.readAsText(blob);
  return promise
}
function readArrayBufferAsText(buf) {
  var view = new Uint8Array(buf);
  var chars = new Array(view.length);
  for (var i = 0; i < view.length; i++) {
    chars[i] = String.fromCharCode(view[i]);
  }
  return chars.join('')
}
function bufferClone(buf) {
  if (buf.slice) {
    return buf.slice(0)
  } else {
    var view = new Uint8Array(buf.byteLength);
    view.set(new Uint8Array(buf));
    return view.buffer
  }
}
function Body() {
  this.bodyUsed = false;
  this._initBody = function(body) {
    this._bodyInit = body;
    if (!body) {
      this._bodyText = '';
    } else if (typeof body === 'string') {
      this._bodyText = body;
    } else if (support.blob && Blob.prototype.isPrototypeOf(body)) {
      this._bodyBlob = body;
    } else if (support.formData && FormData.prototype.isPrototypeOf(body)) {
      this._bodyFormData = body;
    } else if (support.searchParams && URLSearchParams.prototype.isPrototypeOf(body)) {
      this._bodyText = body.toString();
    } else if (support.arrayBuffer && support.blob && isDataView(body)) {
      this._bodyArrayBuffer = bufferClone(body.buffer);
      // IE 10-11 can't handle a DataView body.
      this._bodyInit = new Blob([this._bodyArrayBuffer]);
    } else if (support.arrayBuffer && (ArrayBuffer.prototype.isPrototypeOf(body) || isArrayBufferView(body))) {
      this._bodyArrayBuffer = bufferClone(body);
    } else {
      this._bodyText = body = Object.prototype.toString.call(body);
    }
    if (!this.headers.get('content-type')) {
      if (typeof body === 'string') {
        this.headers.set('content-type', 'text/plain;charset=UTF-8');
      } else if (this._bodyBlob && this._bodyBlob.type) {
        this.headers.set('content-type', this._bodyBlob.type);
      } else if (support.searchParams && URLSearchParams.prototype.isPrototypeOf(body)) {
        this.headers.set('content-type', 'application/x-www-form-urlencoded;charset=UTF-8');
      }
    }
  };
  if (support.blob) {
    this.blob = function() {
      var rejected = consumed(this);
      if (rejected) {
        return rejected
      }
      if (this._bodyBlob) {
        return Promise.resolve(this._bodyBlob)
      } else if (this._bodyArrayBuffer) {
        return Promise.resolve(new Blob([this._bodyArrayBuffer]))
      } else if (this._bodyFormData) {
        throw new Error('could not read FormData body as blob')
      } else {
        return Promise.resolve(new Blob([this._bodyText]))
      }
    };
    this.arrayBuffer = function() {
      if (this._bodyArrayBuffer) {
        return consumed(this) || Promise.resolve(this._bodyArrayBuffer)
      } else {
        return this.blob().then(readBlobAsArrayBuffer)
      }
    };
  }
  this.text = function() {
    var rejected = consumed(this);
    if (rejected) {
      return rejected
    }
    if (this._bodyBlob) {
      return readBlobAsText(this._bodyBlob)
    } else if (this._bodyArrayBuffer) {
      return Promise.resolve(readArrayBufferAsText(this._bodyArrayBuffer))
    } else if (this._bodyFormData) {
      throw new Error('could not read FormData body as text')
    } else {
      return Promise.resolve(this._bodyText)
    }
  };
  if (support.formData) {
    this.formData = function() {
      return this.text().then(decode)
    };
  }
  this.json = function() {
    return this.text().then(JSON.parse)
  };
  return this
}
// HTTP methods whose capitalization should be normalized
var methods = ['DELETE', 'GET', 'HEAD', 'OPTIONS', 'POST', 'PUT'];
function normalizeMethod(method) {
  var upcased = method.toUpperCase();
  return methods.indexOf(upcased) > -1 ? upcased : method
}
function Request(input, options) {
  options = options || {};
  var body = options.body;
  if (input instanceof Request) {
    if (input.bodyUsed) {
      throw new TypeError('Already read')
    }
    this.url = input.url;
    this.credentials = input.credentials;
    if (!options.headers) {
      this.headers = new Headers(input.headers);
    }
    this.method = input.method;
    this.mode = input.mode;
    this.signal = input.signal;
    if (!body && input._bodyInit != null) {
      body = input._bodyInit;
      input.bodyUsed = true;
    }
  } else {
    this.url = String(input);
  }
  this.credentials = options.credentials || this.credentials || 'same-origin';
  if (options.headers || !this.headers) {
    this.headers = new Headers(options.headers);
  }
  this.method = normalizeMethod(options.method || this.method || 'GET');
  this.mode = options.mode || this.mode || null;
  this.signal = options.signal || this.signal;
  this.referrer = null;
  if ((this.method === 'GET' || this.method === 'HEAD') && body) {
    throw new TypeError('Body not allowed for GET or HEAD requests')
  }
  this._initBody(body);
}
Request.prototype.clone = function() {
  return new Request(this, {body: this._bodyInit})
};
function decode(body) {
  var form = new FormData();
  body
    .trim()
    .split('&')
    .forEach(function(bytes) {
      if (bytes) {
        var split = bytes.split('=');
        var name = split.shift().replace(/\+/g, ' ');
        var value = split.join('=').replace(/\+/g, ' ');
        form.append(decodeURIComponent(name), decodeURIComponent(value));
      }
    });
  return form
}
function parseHeaders(rawHeaders) {
  var headers = new Headers();
  // Replace instances of \r\n and \n followed by at least one space or horizontal tab with a space
  // https://tools.ietf.org/html/rfc7230#section-3.2
  var preProcessedHeaders = rawHeaders.replace(/\r?\n[\t ]+/g, ' ');
  preProcessedHeaders.split(/\r?\n/).forEach(function(line) {
    var parts = line.split(':');
    var key = parts.shift().trim();
    if (key) {
      var value = parts.join(':').trim();
      headers.append(key, value);
    }
  });
  return headers
}
Body.call(Request.prototype);
function Response(bodyInit, options) {
  if (!options) {
    options = {};
  }
  this.type = 'default';
  this.status = options.status === undefined ? 200 : options.status;
  this.ok = this.status >= 200 && this.status < 300;
  this.statusText = 'statusText' in options ? options.statusText : 'OK';
  this.headers = new Headers(options.headers);
  this.url = options.url || '';
  this._initBody(bodyInit);
}
Body.call(Response.prototype);
Response.prototype.clone = function() {
  return new Response(this._bodyInit, {
    status: this.status,
    statusText: this.statusText,
    headers: new Headers(this.headers),
    url: this.url
  })
};
Response.error = function() {
  var response = new Response(null, {status: 0, statusText: ''});
  response.type = 'error';
  return response
};
var redirectStatuses = [301, 302, 303, 307, 308];
Response.redirect = function(url, status) {
  if (redirectStatuses.indexOf(status) === -1) {
    throw new RangeError('Invalid status code')
  }
  return new Response(null, {status: status, headers: {location: url}})
};
exports.DOMException = self.DOMException;
try {
  new exports.DOMException();
} catch (err) {
  exports.DOMException = function(message, name) {
    this.message = message;
    this.name = name;
    var error = Error(message);
    this.stack = error.stack;
  };
  exports.DOMException.prototype = Object.create(Error.prototype);
  exports.DOMException.prototype.constructor = exports.DOMException;
}
function fetch(input, init) {
  return new Promise(function(resolve, reject) {
    var request = new Request(input, init);
    if (request.signal && request.signal.aborted) {
      return reject(new exports.DOMException('Aborted', 'AbortError'))
    }
    var xhr = new XMLHttpRequest();
    function abortXhr() {
      xhr.abort();
    }
    xhr.onload = function() {
      var options = {
        status: xhr.status,
        statusText: xhr.statusText,
        headers: parseHeaders(xhr.getAllResponseHeaders() || '')
      };
      options.url = 'responseURL' in xhr ? xhr.responseURL : options.headers.get('X-Request-URL');
      var body = 'response' in xhr ? xhr.response : xhr.responseText;
      resolve(new Response(body, options));
    };
    xhr.onerror = function() {
      reject(new TypeError('Network request failed'));
    };
    xhr.ontimeout = function() {
      reject(new TypeError('Network request failed'));
    };
    xhr.onabort = function() {
      reject(new exports.DOMException('Aborted', 'AbortError'));
    };
    xhr.open(request.method, request.url, true);
    if (request.credentials === 'include') {
      xhr.withCredentials = true;
    } else if (request.credentials === 'omit') {
      xhr.withCredentials = false;
    }
    if ('responseType' in xhr && support.blob) {
      xhr.responseType = 'blob';
    }
    request.headers.forEach(function(value, name) {
      xhr.setRequestHeader(name, value);
    });
    if (request.signal) {
      request.signal.addEventListener('abort', abortXhr);
      xhr.onreadystatechange = function() {
        // DONE (success or failure)
        if (xhr.readyState === 4) {
          request.signal.removeEventListener('abort', abortXhr);
        }
      };
    }
    xhr.send(typeof request._bodyInit === 'undefined' ? null : request._bodyInit);
  })
}
fetch.polyfill = true;
if (!self.fetch) {
  self.fetch = fetch;
  self.Headers = Headers;
  self.Request = Request;
  self.Response = Response;
}
exports.Headers = Headers;
exports.Request = Request;
exports.Response = Response;
exports.fetch = fetch;
Object.defineProperty(exports, '__esModule', { value: true });

})));