Axios ES2017 (#4787)

* Added AxiosHeaders class;

* Fixed README.md href;

* Fixed a potential bug with headers normalization;

* Fixed a potential bug with headers normalization;
Refactored accessor building routine;
Refactored default transforms;
Removed `normalizeHeaderName` helper;

* Added `Content-Length` accessor;
Added missed `has` accessor to TS types;

* Added `AxiosTransformStream` class;
Added progress capturing ability for node.js environment;
Added `maxRate` option to limit the data rate in node.js environment;
Refactored event handled by `onUploadProgress` && `onDownloadProgress` listeners in browser environment;
Added progress & data rate tests for the http adapter;
Added response stream aborting test;
Added a manual progress capture test for the browser;
Updated TS types;
Added TS tests;
Refactored request abort logic for the http adapter;
Added ability to abort the response stream;

* Remove `stream/promises` & `timers/promises` modules usage in tests;

* Use `abortcontroller-polyfill`;

* Fixed AxiosTransformStream dead-lock in legacy node versions;
Fixed CancelError emitting in streams;

* Reworked AxiosTransformStream internal logic to optimize memory consumption;
Added throwing an error if the request stream was silently destroying (without error) Refers to #3966;

* Treat the destruction of the request stream as a cancellation of the request;
Fixed tests;

* Emit `progress` event in the next tick;

* Initial refactoring;

* Refactored Mocha tests to use ESM;

* Refactored Karma tests to use rollup preprocessor & ESM;
Replaced grunt with gulp;
Improved dev scripts;
Added Babel for rollup build;

* Added default commonjs package export for Node build;
Added automatic contributors list generator for package.json;

Co-authored-by: Jay <jasonsaayman@gmail.com>

lib/helpers/AxiosTransformStream.js

@@ -0,0 +1,191 @@
+'use strict';
+
+import stream from 'stream';
+import utils from '../utils.js';
+import throttle from './throttle.js';
+import speedometer from './speedometer.js';
+
+const kInternals = Symbol('internals');
+
+class AxiosTransformStream extends stream.Transform{
+  constructor(options) {
+    options = utils.toFlatObject(options, {
+      maxRate: 0,
+      chunkSize: 64 * 1024,
+      minChunkSize: 100,
+      timeWindow: 500,
+      ticksRate: 2,
+      samplesCount: 15
+    }, null, (prop, source) => {
+      return !utils.isUndefined(source[prop]);
+    });
+
+    super({
+      readableHighWaterMark: options.chunkSize
+    });
+
+    const self = this;
+
+    const internals = this[kInternals] = {
+      length: options.length,
+      timeWindow: options.timeWindow,
+      ticksRate: options.ticksRate,
+      chunkSize: options.chunkSize,
+      maxRate: options.maxRate,
+      minChunkSize: options.minChunkSize,
+      bytesSeen: 0,
+      isCaptured: false,
+      notifiedBytesLoaded: 0,
+      ts: Date.now(),
+      bytes: 0,
+      onReadCallback: null
+    };
+
+    const _speedometer = speedometer(internals.ticksRate * options.samplesCount, internals.timeWindow);
+
+    this.on('newListener', event => {
+      if (event === 'progress') {
+        if (!internals.isCaptured) {
+          internals.isCaptured = true;
+        }
+      }
+    });
+
+    let bytesNotified = 0;
+
+    internals.updateProgress = throttle(function throttledHandler() {
+      const totalBytes = internals.length;
+      const bytesTransferred = internals.bytesSeen;
+      const progressBytes = bytesTransferred - bytesNotified;
+      if (!progressBytes || self.destroyed) return;
+
+      const rate = _speedometer(progressBytes);
+
+      bytesNotified = bytesTransferred;
+
+      process.nextTick(() => {
+        self.emit('progress', {
+          'loaded': bytesTransferred,
+          'total': totalBytes,
+          'progress': totalBytes ? (bytesTransferred / totalBytes) : undefined,
+          'bytes': progressBytes,
+          'rate': rate ? rate : undefined,
+          'estimated': rate && totalBytes && bytesTransferred <= totalBytes ?
+            (totalBytes - bytesTransferred) / rate : undefined
+        });
+      });
+    }, internals.ticksRate);
+
+    const onFinish = () => {
+      internals.updateProgress(true);
+    };
+
+    this.once('end', onFinish);
+    this.once('error', onFinish);
+  }
+
+  _read(size) {
+    const internals = this[kInternals];
+
+    if (internals.onReadCallback) {
+      internals.onReadCallback();
+    }
+
+    return super._read(size);
+  }
+
+  _transform(chunk, encoding, callback) {
+    const self = this;
+    const internals = this[kInternals];
+    const maxRate = internals.maxRate;
+
+    const readableHighWaterMark = this.readableHighWaterMark;
+
+    const timeWindow = internals.timeWindow;
+
+    const divider = 1000 / timeWindow;
+    const bytesThreshold = (maxRate / divider);
+    const minChunkSize = internals.minChunkSize !== false ? Math.max(internals.minChunkSize, bytesThreshold * 0.01) : 0;
+
+    function pushChunk(_chunk, _callback) {
+      const bytes = Buffer.byteLength(_chunk);
+      internals.bytesSeen += bytes;
+      internals.bytes += bytes;
+
+      if (internals.isCaptured) {
+        internals.updateProgress();
+      }
+
+      if (self.push(_chunk)) {
+        process.nextTick(_callback);
+      } else {
+        internals.onReadCallback = () => {
+          internals.onReadCallback = null;
+          process.nextTick(_callback);
+        };
+      }
+    }
+
+    const transformChunk = (_chunk, _callback) => {
+      const chunkSize = Buffer.byteLength(_chunk);
+      let chunkRemainder = null;
+      let maxChunkSize = readableHighWaterMark;
+      let bytesLeft;
+      let passed = 0;
+
+      if (maxRate) {
+        const now = Date.now();
+
+        if (!internals.ts || (passed = (now - internals.ts)) >= timeWindow) {
+          internals.ts = now;
+          bytesLeft = bytesThreshold - internals.bytes;
+          internals.bytes = bytesLeft < 0 ? -bytesLeft : 0;
+          passed = 0;
+        }
+
+        bytesLeft = bytesThreshold - internals.bytes;
+      }
+
+      if (maxRate) {
+        if (bytesLeft <= 0) {
+          // next time window
+          return setTimeout(() => {
+            _callback(null, _chunk);
+          }, timeWindow - passed);
+        }
+
+        if (bytesLeft < maxChunkSize) {
+          maxChunkSize = bytesLeft;
+        }
+      }
+
+      if (maxChunkSize && chunkSize > maxChunkSize && (chunkSize - maxChunkSize) > minChunkSize) {
+        chunkRemainder = _chunk.subarray(maxChunkSize);
+        _chunk = _chunk.subarray(0, maxChunkSize);
+      }
+
+      pushChunk(_chunk, chunkRemainder ? () => {
+        process.nextTick(_callback, null, chunkRemainder);
+      } : _callback);
+    };
+
+    transformChunk(chunk, function transformNextChunk(err, _chunk) {
+      if (err) {
+        return callback(err);
+      }
+
+      if (_chunk) {
+        transformChunk(_chunk, transformNextChunk);
+      } else {
+        callback(null);
+      }
+    });
+  }
+
+  setLength(length) {
+    this[kInternals].length = +length;
+    return this;
+  }
+}
+
+export default AxiosTransformStream;

lib/helpers/AxiosURLSearchParams.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var toFormData = require('./toFormData');
+import toFormData from './toFormData.js';
 
 /**
  * It encodes a string by replacing all characters that are not in the unreserved set with
@@ -11,7 +11,7 @@ var toFormData = require('./toFormData');
  * @returns {string} The encoded string.
  */
 function encode(str) {
-  var charMap = {
+  const charMap = {
     '!': '%21',
     "'": '%27',
     '(': '%28',
@@ -20,7 +20,7 @@ function encode(str) {
     '%20': '+',
     '%00': '\x00'
   };
-  return encodeURIComponent(str).replace(/[!'\(\)~]|%20|%00/g, function replacer(match) {
+  return encodeURIComponent(str).replace(/[!'()~]|%20|%00/g, function replacer(match) {
     return charMap[match];
   });
 }
@@ -39,14 +39,14 @@ function AxiosURLSearchParams(params, options) {
   params && toFormData(params, this, options);
 }
 
-var prototype = AxiosURLSearchParams.prototype;
+const prototype = AxiosURLSearchParams.prototype;
 
 prototype.append = function append(name, value) {
   this._pairs.push([name, value]);
 };
 
 prototype.toString = function toString(encoder) {
-  var _encode = encoder ? function(value) {
+  const _encode = encoder ? function(value) {
     return encoder.call(this, value, encode);
   } : encode;
 
@@ -55,4 +55,4 @@ prototype.toString = function toString(encoder) {
   }, '').join('&');
 };
 
-module.exports = AxiosURLSearchParams;
+export default AxiosURLSearchParams;

lib/helpers/bind.js

@@ -1,7 +1,7 @@
 'use strict';
 
-module.exports = function bind(fn, thisArg) {
+export default function bind(fn, thisArg) {
   return function wrap() {
     return fn.apply(thisArg, arguments);
   };
-};
+}

lib/helpers/buildURL.js

@@ -1,7 +1,7 @@
 'use strict';
 
-var utils = require('../utils');
-var AxiosURLSearchParams = require('../helpers/AxiosURLSearchParams');
+import utils from '../utils.js';
+import AxiosURLSearchParams from '../helpers/AxiosURLSearchParams.js';
 
 /**
  * It replaces all instances of the characters `:`, `$`, `,`, `+`, `[`, and `]` with their
@@ -30,21 +30,21 @@ function encode(val) {
  *
  * @returns {string} The formatted url
  */
-module.exports = function buildURL(url, params, options) {
+export default function buildURL(url, params, options) {
   /*eslint no-param-reassign:0*/
   if (!params) {
     return url;
   }
 
-  var hashmarkIndex = url.indexOf('#');
+  const hashmarkIndex = url.indexOf('#');
 
   if (hashmarkIndex !== -1) {
     url = url.slice(0, hashmarkIndex);
   }
 
-  var _encode = options && options.encode || encode;
+  const _encode = options && options.encode || encode;
 
-  var serializerParams = utils.isURLSearchParams(params) ?
+  const serializerParams = utils.isURLSearchParams(params) ?
     params.toString() :
     new AxiosURLSearchParams(params, options).toString(_encode);
 
@@ -53,4 +53,4 @@ module.exports = function buildURL(url, params, options) {
   }
 
   return url;
-};
+}

lib/helpers/combineURLs.js

@@ -8,8 +8,8 @@
  *
  * @returns {string} The combined URL
  */
-module.exports = function combineURLs(baseURL, relativeURL) {
+export default function combineURLs(baseURL, relativeURL) {
   return relativeURL
     ? baseURL.replace(/\/+$/, '') + '/' + relativeURL.replace(/^\/+/, '')
     : baseURL;
-};
+}

lib/helpers/cookies.js

@@ -1,53 +1,51 @@
 'use strict';
 
-var utils = require('./../utils');
+import utils from './../utils.js';
 
-module.exports = (
-  utils.isStandardBrowserEnv() ?
+export default utils.isStandardBrowserEnv() ?
 
-  // Standard browser envs support document.cookie
-    (function standardBrowserEnv() {
-      return {
-        write: function write(name, value, expires, path, domain, secure) {
-          var cookie = [];
-          cookie.push(name + '=' + encodeURIComponent(value));
+// Standard browser envs support document.cookie
+  (function standardBrowserEnv() {
+    return {
+      write: function write(name, value, expires, path, domain, secure) {
+        const cookie = [];
+        cookie.push(name + '=' + encodeURIComponent(value));
 
-          if (utils.isNumber(expires)) {
-            cookie.push('expires=' + new Date(expires).toGMTString());
-          }
-
-          if (utils.isString(path)) {
-            cookie.push('path=' + path);
-          }
-
-          if (utils.isString(domain)) {
-            cookie.push('domain=' + domain);
-          }
-
-          if (secure === true) {
-            cookie.push('secure');
-          }
-
-          document.cookie = cookie.join('; ');
-        },
-
-        read: function read(name) {
-          var match = document.cookie.match(new RegExp('(^|;\\s*)(' + name + ')=([^;]*)'));
-          return (match ? decodeURIComponent(match[3]) : null);
-        },
-
-        remove: function remove(name) {
-          this.write(name, '', Date.now() - 86400000);
+        if (utils.isNumber(expires)) {
+          cookie.push('expires=' + new Date(expires).toGMTString());
         }
-      };
-    })() :
 
-  // Non standard browser env (web workers, react-native) lack needed support.
-    (function nonStandardBrowserEnv() {
-      return {
-        write: function write() {},
-        read: function read() { return null; },
-        remove: function remove() {}
-      };
-    })()
-);
+        if (utils.isString(path)) {
+          cookie.push('path=' + path);
+        }
+
+        if (utils.isString(domain)) {
+          cookie.push('domain=' + domain);
+        }
+
+        if (secure === true) {
+          cookie.push('secure');
+        }
+
+        document.cookie = cookie.join('; ');
+      },
+
+      read: function read(name) {
+        const match = document.cookie.match(new RegExp('(^|;\\s*)(' + name + ')=([^;]*)'));
+        return (match ? decodeURIComponent(match[3]) : null);
+      },
+
+      remove: function remove(name) {
+        this.write(name, '', Date.now() - 86400000);
+      }
+    };
+  })() :
+
+// Non standard browser env (web workers, react-native) lack needed support.
+  (function nonStandardBrowserEnv() {
+    return {
+      write: function write() {},
+      read: function read() { return null; },
+      remove: function remove() {}
+    };
+  })();

lib/helpers/deprecatedMethod.js

@@ -12,7 +12,7 @@
  *
  * @returns {void}
  */
-module.exports = function deprecatedMethod(method, instead, docs) {
+export default function deprecatedMethod(method, instead, docs) {
   try {
     console.warn(
       'DEPRECATED method `' + method + '`.' +
@@ -23,4 +23,4 @@ module.exports = function deprecatedMethod(method, instead, docs) {
       console.warn('For more information about usage see ' + docs);
     }
   } catch (e) { /* Ignore */ }
-};
+}

lib/helpers/formDataToJSON.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var utils = require('../utils');
+import utils from '../utils.js';
 
 /**
  * It takes a string like `foo[x][y][z]` and returns an array like `['foo', 'x', 'y', 'z']
@@ -14,7 +14,7 @@ function parsePropPath(name) {
   // foo.x.y.z
   // foo-x-y-z
   // foo x y z
-  return utils.matchAll(/\w+|\[(\w*)]/g, name).map(function(match) {
+  return utils.matchAll(/\w+|\[(\w*)]/g, name).map(match => {
     return match[0] === '[]' ? '' : match[1] || match[0];
   });
 }
@@ -27,11 +27,11 @@ function parsePropPath(name) {
  * @returns An object with the same keys and values as the array.
  */
 function arrayToObject(arr) {
-  var obj = {};
-  var keys = Object.keys(arr);
-  var i;
-  var len = keys.length;
-  var key;
+  const obj = {};
+  const keys = Object.keys(arr);
+  let i;
+  const len = keys.length;
+  let key;
   for (i = 0; i < len; i++) {
     key = keys[i];
     obj[key] = arr[key];
@@ -48,13 +48,13 @@ function arrayToObject(arr) {
  */
 function formDataToJSON(formData) {
   function buildPath(path, value, target, index) {
-    var name = path[index++];
-    var isNumericKey = Number.isFinite(+name);
-    var isLast = index >= path.length;
+    let name = path[index++];
+    const isNumericKey = Number.isFinite(+name);
+    const isLast = index >= path.length;
     name = !name && utils.isArray(target) ? target.length : name;
 
     if (isLast) {
-      if (utils.hasOwnProperty(target, name)) {
+      if (utils.hasOwnProp(target, name)) {
         target[name] = [target[name], value];
       } else {
         target[name] = value;
@@ -67,7 +67,7 @@ function formDataToJSON(formData) {
       target[name] = [];
     }
 
-    var result = buildPath(path, value, target[name], index);
+    const result = buildPath(path, value, target[name], index);
 
     if (result && utils.isArray(target[name])) {
       target[name] = arrayToObject(target[name]);
@@ -77,9 +77,9 @@ function formDataToJSON(formData) {
   }
 
   if (utils.isFormData(formData) && utils.isFunction(formData.entries)) {
-    var obj = {};
+    const obj = {};
 
-    utils.forEachEntry(formData, function(name, value) {
+    utils.forEachEntry(formData, (name, value) => {
       buildPath(parsePropPath(name), value, obj, 0);
     });
 
@@ -89,4 +89,4 @@ function formDataToJSON(formData) {
   return null;
 }
 
-module.exports = formDataToJSON;
+export default formDataToJSON;

lib/helpers/fromDataURI.js

@@ -1,10 +1,10 @@
 'use strict';
 
-var AxiosError = require('../core/AxiosError');
-var parseProtocol = require('./parseProtocol');
-var platform = require('../platform');
+import AxiosError from '../core/AxiosError.js';
+import parseProtocol from './parseProtocol.js';
+import platform from '../platform/index.js';
 
-var DATA_URL_PATTERN = /^(?:([^;]+);)?(?:[^;]+;)?(base64|),([\s\S]*)$/;
+const DATA_URL_PATTERN = /^(?:([^;]+);)?(?:[^;]+;)?(base64|),([\s\S]*)$/;
 
 /**
  * Parse data uri to a Buffer or Blob
@@ -16,9 +16,9 @@ var DATA_URL_PATTERN = /^(?:([^;]+);)?(?:[^;]+;)?(base64|),([\s\S]*)$/;
  *
  * @returns {Buffer|Blob}
  */
-module.exports = function fromDataURI(uri, asBlob, options) {
-  var _Blob = options && options.Blob || platform.classes.Blob;
-  var protocol = parseProtocol(uri);
+export default function fromDataURI(uri, asBlob, options) {
+  const _Blob = options && options.Blob || platform.classes.Blob;
+  const protocol = parseProtocol(uri);
 
   if (asBlob === undefined && _Blob) {
     asBlob = true;
@@ -27,16 +27,16 @@ module.exports = function fromDataURI(uri, asBlob, options) {
   if (protocol === 'data') {
     uri = protocol.length ? uri.slice(protocol.length + 1) : uri;
 
-    var match = DATA_URL_PATTERN.exec(uri);
+    const match = DATA_URL_PATTERN.exec(uri);
 
     if (!match) {
       throw new AxiosError('Invalid URL', AxiosError.ERR_INVALID_URL);
     }
 
-    var mime = match[1];
-    var isBase64 = match[2];
-    var body = match[3];
-    var buffer = Buffer.from(decodeURIComponent(body), isBase64 ? 'base64' : 'utf8');
+    const mime = match[1];
+    const isBase64 = match[2];
+    const body = match[3];
+    const buffer = Buffer.from(decodeURIComponent(body), isBase64 ? 'base64' : 'utf8');
 
     if (asBlob) {
       if (!_Blob) {
@@ -50,4 +50,4 @@ module.exports = function fromDataURI(uri, asBlob, options) {
   }
 
   throw new AxiosError('Unsupported protocol ' + protocol, AxiosError.ERR_NOT_SUPPORT);
-};
+}

lib/helpers/isAbsoluteURL.js

@@ -7,9 +7,9 @@
  *
  * @returns {boolean} True if the specified URL is absolute, otherwise false
  */
-module.exports = function isAbsoluteURL(url) {
+export default function isAbsoluteURL(url) {
   // A URL is considered absolute if it begins with "<scheme>://" or "//" (protocol-relative URL).
   // RFC 3986 defines scheme name as a sequence of characters beginning with a letter and followed
   // by any combination of letters, digits, plus, period, or hyphen.
   return /^([a-z][a-z\d+\-.]*:)?\/\//i.test(url);
-};
+}

lib/helpers/isAxiosError.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var utils = require('./../utils');
+import utils from './../utils.js';
 
 /**
  * Determines whether the payload is an error thrown by Axios
@@ -9,6 +9,6 @@ var utils = require('./../utils');
  *
  * @returns {boolean} True if the payload is an error thrown by Axios, otherwise false
  */
-module.exports = function isAxiosError(payload) {
+export default function isAxiosError(payload) {
   return utils.isObject(payload) && (payload.isAxiosError === true);
-};
+}

lib/helpers/isURLSameOrigin.js

@@ -1,68 +1,66 @@
 'use strict';
 
-var utils = require('./../utils');
+import utils from './../utils.js';
 
-module.exports = (
-  utils.isStandardBrowserEnv() ?
+export default utils.isStandardBrowserEnv() ?
 
-  // Standard browser envs have full support of the APIs needed to test
-  // whether the request URL is of the same origin as current location.
-    (function standardBrowserEnv() {
-      var msie = /(msie|trident)/i.test(navigator.userAgent);
-      var urlParsingNode = document.createElement('a');
-      var originURL;
+// Standard browser envs have full support of the APIs needed to test
+// whether the request URL is of the same origin as current location.
+  (function standardBrowserEnv() {
+    const msie = /(msie|trident)/i.test(navigator.userAgent);
+    const urlParsingNode = document.createElement('a');
+    let originURL;
 
-      /**
-      * Parse a URL to discover it's components
-      *
-      * @param {String} url The URL to be parsed
-      * @returns {Object}
-      */
-      function resolveURL(url) {
-        var href = url;
-
-        if (msie) {
-          // IE needs attribute set twice to normalize properties
-          urlParsingNode.setAttribute('href', href);
-          href = urlParsingNode.href;
-        }
+    /**
+    * Parse a URL to discover it's components
+    *
+    * @param {String} url The URL to be parsed
+    * @returns {Object}
+    */
+    function resolveURL(url) {
+      let href = url;
 
+      if (msie) {
+        // IE needs attribute set twice to normalize properties
         urlParsingNode.setAttribute('href', href);
-
-        // urlParsingNode provides the UrlUtils interface - http://url.spec.whatwg.org/#urlutils
-        return {
-          href: urlParsingNode.href,
-          protocol: urlParsingNode.protocol ? urlParsingNode.protocol.replace(/:$/, '') : '',
-          host: urlParsingNode.host,
-          search: urlParsingNode.search ? urlParsingNode.search.replace(/^\?/, '') : '',
-          hash: urlParsingNode.hash ? urlParsingNode.hash.replace(/^#/, '') : '',
-          hostname: urlParsingNode.hostname,
-          port: urlParsingNode.port,
-          pathname: (urlParsingNode.pathname.charAt(0) === '/') ?
-            urlParsingNode.pathname :
-            '/' + urlParsingNode.pathname
-        };
+        href = urlParsingNode.href;
       }
 
-      originURL = resolveURL(window.location.href);
+      urlParsingNode.setAttribute('href', href);
 
-      /**
-      * Determine if a URL shares the same origin as the current location
-      *
-      * @param {String} requestURL The URL to test
-      * @returns {boolean} True if URL shares the same origin, otherwise false
-      */
-      return function isURLSameOrigin(requestURL) {
-        var parsed = (utils.isString(requestURL)) ? resolveURL(requestURL) : requestURL;
-        return (parsed.protocol === originURL.protocol &&
-            parsed.host === originURL.host);
+      // urlParsingNode provides the UrlUtils interface - http://url.spec.whatwg.org/#urlutils
+      return {
+        href: urlParsingNode.href,
+        protocol: urlParsingNode.protocol ? urlParsingNode.protocol.replace(/:$/, '') : '',
+        host: urlParsingNode.host,
+        search: urlParsingNode.search ? urlParsingNode.search.replace(/^\?/, '') : '',
+        hash: urlParsingNode.hash ? urlParsingNode.hash.replace(/^#/, '') : '',
+        hostname: urlParsingNode.hostname,
+        port: urlParsingNode.port,
+        pathname: (urlParsingNode.pathname.charAt(0) === '/') ?
+          urlParsingNode.pathname :
+          '/' + urlParsingNode.pathname
       };
-    })() :
+    }
 
-    // Non standard browser envs (web workers, react-native) lack needed support.
-    (function nonStandardBrowserEnv() {
-      return function isURLSameOrigin() {
-        return true;
-      };
-    })()
-);
+    originURL = resolveURL(window.location.href);
+
+    /**
+    * Determine if a URL shares the same origin as the current location
+    *
+    * @param {String} requestURL The URL to test
+    * @returns {boolean} True if URL shares the same origin, otherwise false
+    */
+    return function isURLSameOrigin(requestURL) {
+      const parsed = (utils.isString(requestURL)) ? resolveURL(requestURL) : requestURL;
+      return (parsed.protocol === originURL.protocol &&
+          parsed.host === originURL.host);
+    };
+  })() :
+
+  // Non standard browser envs (web workers, react-native) lack needed support.
+  (function nonStandardBrowserEnv() {
+    return function isURLSameOrigin() {
+      return true;
+    };
+  })();

lib/helpers/normalizeHeaderName.js

@@ -1,12 +0,0 @@
-'use strict';
-
-var utils = require('../utils');
-
-module.exports = function normalizeHeaderName(headers, normalizedName) {
-  utils.forEach(headers, function processHeader(value, name) {
-    if (name !== normalizedName && name.toUpperCase() === normalizedName.toUpperCase()) {
-      headers[normalizedName] = value;
-      delete headers[name];
-    }
-  });
-};

lib/helpers/null.js

@@ -1,2 +1,2 @@
 // eslint-disable-next-line strict
-module.exports = null;
+export default null;

lib/helpers/parseHeaders.js

@@ -1,15 +1,15 @@
 'use strict';
 
-var utils = require('./../utils');
+import utils from './../utils.js';
 
-// Headers whose duplicates are ignored by node
+// RawAxiosHeaders whose duplicates are ignored by node
 // c.f. https://nodejs.org/api/http.html#http_message_headers
-var ignoreDuplicateOf = [
+const ignoreDuplicateOf = utils.toObjectSet([
   'age', 'authorization', 'content-length', 'content-type', 'etag',
   'expires', 'from', 'host', 'if-modified-since', 'if-unmodified-since',
   'last-modified', 'location', 'max-forwards', 'proxy-authorization',
   'referer', 'retry-after', 'user-agent'
-];
+]);
 
 /**
  * Parse headers into an object
@@ -21,32 +21,33 @@ var ignoreDuplicateOf = [
  * Transfer-Encoding: chunked
  * ```
  *
- * @param {String} headers Headers needing to be parsed
+ * @param {String} rawHeaders Headers needing to be parsed
  *
  * @returns {Object} Headers parsed into an object
  */
-module.exports = function parseHeaders(headers) {
-  var parsed = {};
-  var key;
-  var val;
-  var i;
+export default rawHeaders => {
+  const parsed = {};
+  let key;
+  let val;
+  let i;
 
-  if (!headers) { return parsed; }
-
-  utils.forEach(headers.split('\n'), function parser(line) {
+  rawHeaders && rawHeaders.split('\n').forEach(function parser(line) {
     i = line.indexOf(':');
-    key = utils.trim(line.slice(0, i)).toLowerCase();
-    val = utils.trim(line.slice(i + 1));
+    key = line.substring(0, i).trim().toLowerCase();
+    val = line.substring(i + 1).trim();
 
-    if (key) {
-      if (parsed[key] && ignoreDuplicateOf.indexOf(key) >= 0) {
-        return;
-      }
-      if (key === 'set-cookie') {
-        parsed[key] = (parsed[key] ? parsed[key] : []).concat([val]);
+    if (!key || (parsed[key] && ignoreDuplicateOf[key])) {
+      return;
+    }
+
+    if (key === 'set-cookie') {
+      if (parsed[key]) {
+        parsed[key].push(val);
       } else {
-        parsed[key] = parsed[key] ? parsed[key] + ', ' + val : val;
+        parsed[key] = [val];
       }
+    } else {
+      parsed[key] = parsed[key] ? parsed[key] + ', ' + val : val;
     }
   });
 

lib/helpers/parseProtocol.js

@@ -1,6 +1,6 @@
 'use strict';
 
-module.exports = function parseProtocol(url) {
-  var match = /^([-+\w]{1,25})(:?\/\/|:)/.exec(url);
+export default function parseProtocol(url) {
+  const match = /^([-+\w]{1,25})(:?\/\/|:)/.exec(url);
   return match && match[1] || '';
-};
+}

lib/helpers/speedometer.js

@@ -0,0 +1,55 @@
+'use strict';
+
+/**
+ * Calculate data maxRate
+ * @param {Number} [samplesCount= 10]
+ * @param {Number} [min= 1000]
+ * @returns {Function}
+ */
+function speedometer(samplesCount, min) {
+  samplesCount = samplesCount || 10;
+  const bytes = new Array(samplesCount);
+  const timestamps = new Array(samplesCount);
+  let head = 0;
+  let tail = 0;
+  let firstSampleTS;
+
+  min = min !== undefined ? min : 1000;
+
+  return function push(chunkLength) {
+    const now = Date.now();
+
+    const startedAt = timestamps[tail];
+
+    if (!firstSampleTS) {
+      firstSampleTS = now;
+    }
+
+    bytes[head] = chunkLength;
+    timestamps[head] = now;
+
+    let i = tail;
+    let bytesCount = 0;
+
+    while (i !== head) {
+      bytesCount += bytes[i++];
+      i = i % samplesCount;
+    }
+
+    head = (head + 1) % samplesCount;
+
+    if (head === tail) {
+      tail = (tail + 1) % samplesCount;
+    }
+
+    if (now - firstSampleTS < min) {
+      return;
+    }
+
+    const passed = startedAt && now - startedAt;
+
+    return  passed ? Math.round(bytesCount * 1000 / passed) : undefined;
+  };
+}
+
+export default speedometer;

lib/helpers/spread.js

@@ -21,8 +21,8 @@
  *
  * @returns {Function}
  */
-module.exports = function spread(callback) {
+export default function spread(callback) {
   return function wrap(arr) {
     return callback.apply(null, arr);
   };
-};
+}

lib/helpers/throttle.js

@@ -0,0 +1,33 @@
+'use strict';
+
+/**
+ * Throttle decorator
+ * @param {Function} fn
+ * @param {Number} freq
+ * @return {Function}
+ */
+function throttle(fn, freq) {
+  let timestamp = 0;
+  const threshold = 1000 / freq;
+  let timer = null;
+  return function throttled(force, args) {
+    const now = Date.now();
+    if (force || now - timestamp > threshold) {
+      if (timer) {
+        clearTimeout(timer);
+        timer = null;
+      }
+      timestamp = now;
+      return fn.apply(null, args);
+    }
+    if (!timer) {
+      timer = setTimeout(() => {
+        timer = null;
+        timestamp = Date.now();
+        return fn.apply(null, args);
+      }, threshold - (now - timestamp));
+    }
+  };
+}
+
+export default throttle;

lib/helpers/toFormData.js

@@ -1,8 +1,8 @@
 'use strict';
 
-var utils = require('../utils');
-var AxiosError = require('../core/AxiosError');
-var envFormData = require('../env/classes/FormData');
+import utils from '../utils.js';
+import AxiosError from '../core/AxiosError.js';
+import envFormData from '../env/classes/FormData.js';
 
 /**
  * Determines if the given thing is a array or js object.
@@ -55,7 +55,7 @@ function isFlatArray(arr) {
   return utils.isArray(arr) && !arr.some(isVisitable);
 }
 
-var predicates = utils.toFlatObject(utils, {}, null, function filter(prop) {
+const predicates = utils.toFlatObject(utils, {}, null, function filter(prop) {
   return /^is[A-Z]/.test(prop);
 });
 
@@ -111,13 +111,13 @@ function toFormData(obj, formData, options) {
     return !utils.isUndefined(source[option]);
   });
 
-  var metaTokens = options.metaTokens;
+  const metaTokens = options.metaTokens;
   // eslint-disable-next-line no-use-before-define
-  var visitor = options.visitor || defaultVisitor;
-  var dots = options.dots;
-  var indexes = options.indexes;
-  var _Blob = options.Blob || typeof Blob !== 'undefined' && Blob;
-  var useBlob = _Blob && isSpecCompliant(formData);
+  const visitor = options.visitor || defaultVisitor;
+  const dots = options.dots;
+  const indexes = options.indexes;
+  const _Blob = options.Blob || typeof Blob !== 'undefined' && Blob;
+  const useBlob = _Blob && isSpecCompliant(formData);
 
   if (!utils.isFunction(visitor)) {
     throw new TypeError('visitor must be a function');
@@ -152,7 +152,7 @@ function toFormData(obj, formData, options) {
    * @returns {boolean} return true to visit the each prop of the value recursively
    */
   function defaultVisitor(value, key, path) {
-    var arr = value;
+    let arr = value;
 
     if (value && !path && typeof value === 'object') {
       if (utils.endsWith(key, '{}')) {
@@ -187,12 +187,12 @@ function toFormData(obj, formData, options) {
     return false;
   }
 
-  var stack = [];
+  const stack = [];
 
-  var exposedHelpers = Object.assign(predicates, {
-    defaultVisitor: defaultVisitor,
-    convertValue: convertValue,
-    isVisitable: isVisitable
+  const exposedHelpers = Object.assign(predicates, {
+    defaultVisitor,
+    convertValue,
+    isVisitable
   });
 
   function build(value, path) {
@@ -205,7 +205,7 @@ function toFormData(obj, formData, options) {
     stack.push(value);
 
     utils.forEach(value, function each(el, key) {
-      var result = !utils.isUndefined(el) && visitor.call(
+      const result = !utils.isUndefined(el) && visitor.call(
         formData, el, utils.isString(key) ? key.trim() : key, path, exposedHelpers
       );
 
@@ -226,4 +226,4 @@ function toFormData(obj, formData, options) {
   return formData;
 }
 
-module.exports = toFormData;
+export default toFormData;

lib/helpers/toURLEncodedForm.js

@@ -1,10 +1,10 @@
 'use strict';
 
-var utils = require('../utils');
-var toFormData = require('./toFormData');
-var platform = require('../platform/');
+import utils from '../utils.js';
+import toFormData from './toFormData.js';
+import platform from '../platform/index.js';
 
-module.exports = function toURLEncodedForm(data, options) {
+export default function toURLEncodedForm(data, options) {
   return toFormData(data, new platform.classes.URLSearchParams(), Object.assign({
     visitor: function(value, key, path, helpers) {
       if (platform.isNode && utils.isBuffer(value)) {
@@ -15,4 +15,4 @@ module.exports = function toURLEncodedForm(data, options) {
       return helpers.defaultVisitor.apply(this, arguments);
     }
   }, options));
-};
+}

lib/helpers/validator.js

@@ -1,18 +1,18 @@
 'use strict';
 
-var VERSION = require('../env/data').version;
-var AxiosError = require('../core/AxiosError');
+import {VERSION} from '../env/data.js';
+import AxiosError from '../core/AxiosError.js';
 
-var validators = {};
+const validators = {};
 
 // eslint-disable-next-line func-names
-['object', 'boolean', 'number', 'function', 'string', 'symbol'].forEach(function(type, i) {
+['object', 'boolean', 'number', 'function', 'string', 'symbol'].forEach((type, i) => {
   validators[type] = function validator(thing) {
     return typeof thing === type || 'a' + (i < 1 ? 'n ' : ' ') + type;
   };
 });
 
-var deprecatedWarnings = {};
+const deprecatedWarnings = {};
 
 /**
  * Transitional option validator
@@ -29,7 +29,7 @@ validators.transitional = function transitional(validator, version, message) {
   }
 
   // eslint-disable-next-line func-names
-  return function(value, opt, opts) {
+  return (value, opt, opts) => {
     if (validator === false) {
       throw new AxiosError(
         formatMessage(opt, ' has been removed' + (version ? ' in ' + version : '')),
@@ -66,14 +66,14 @@ function assertOptions(options, schema, allowUnknown) {
   if (typeof options !== 'object') {
     throw new AxiosError('options must be an object', AxiosError.ERR_BAD_OPTION_VALUE);
   }
-  var keys = Object.keys(options);
-  var i = keys.length;
+  const keys = Object.keys(options);
+  let i = keys.length;
   while (i-- > 0) {
-    var opt = keys[i];
-    var validator = schema[opt];
+    const opt = keys[i];
+    const validator = schema[opt];
     if (validator) {
-      var value = options[opt];
-      var result = value === undefined || validator(value, opt, options);
+      const value = options[opt];
+      const result = value === undefined || validator(value, opt, options);
       if (result !== true) {
         throw new AxiosError('option ' + opt + ' must be ' + result, AxiosError.ERR_BAD_OPTION_VALUE);
       }
@@ -85,7 +85,7 @@ function assertOptions(options, schema, allowUnknown) {
   }
 }
 
-module.exports = {
-  assertOptions: assertOptions,
-  validators: validators
+export default {
+  assertOptions,
+  validators
 };