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/core/Axios.js

@@ -1,14 +1,16 @@
 'use strict';
 
-var utils = require('./../utils');
-var buildURL = require('../helpers/buildURL');
-var InterceptorManager = require('./InterceptorManager');
-var dispatchRequest = require('./dispatchRequest');
-var mergeConfig = require('./mergeConfig');
-var buildFullPath = require('./buildFullPath');
-var validator = require('../helpers/validator');
+import utils from './../utils.js';
+import buildURL from '../helpers/buildURL.js';
+import InterceptorManager from './InterceptorManager.js';
+import dispatchRequest from './dispatchRequest.js';
+import mergeConfig from './mergeConfig.js';
+import buildFullPath from './buildFullPath.js';
+import validator from '../helpers/validator.js';
+import AxiosHeaders from './AxiosHeaders.js';
+
+const validators = validator.validators;
 
-var validators = validator.validators;
 /**
  * Create a new instance of Axios
  *
@@ -16,126 +18,147 @@ var validators = validator.validators;
  *
  * @return {Axios} A new instance of Axios
  */
-function Axios(instanceConfig) {
-  this.defaults = instanceConfig;
-  this.interceptors = {
-    request: new InterceptorManager(),
-    response: new InterceptorManager()
-  };
-}
-
-/**
- * Dispatch a request
- *
- * @param {String|Object} configOrUrl The config specific for this request (merged with this.defaults)
- * @param {?Object} config
- *
- * @returns {Promise} The Promise to be fulfilled
- */
-Axios.prototype.request = function request(configOrUrl, config) {
-  /*eslint no-param-reassign:0*/
-  // Allow for axios('example/url'[, config]) a la fetch API
-  if (typeof configOrUrl === 'string') {
-    config = config || {};
-    config.url = configOrUrl;
-  } else {
-    config = configOrUrl || {};
+class Axios {
+  constructor(instanceConfig) {
+    this.defaults = instanceConfig;
+    this.interceptors = {
+      request: new InterceptorManager(),
+      response: new InterceptorManager()
+    };
   }
 
-  config = mergeConfig(this.defaults, config);
-
-  // Set config.method
-  if (config.method) {
-    config.method = config.method.toLowerCase();
-  } else if (this.defaults.method) {
-    config.method = this.defaults.method.toLowerCase();
-  } else {
-    config.method = 'get';
-  }
-
-  var transitional = config.transitional;
-
-  if (transitional !== undefined) {
-    validator.assertOptions(transitional, {
-      silentJSONParsing: validators.transitional(validators.boolean),
-      forcedJSONParsing: validators.transitional(validators.boolean),
-      clarifyTimeoutError: validators.transitional(validators.boolean)
-    }, false);
-  }
-
-  // filter out skipped interceptors
-  var requestInterceptorChain = [];
-  var synchronousRequestInterceptors = true;
-  this.interceptors.request.forEach(function unshiftRequestInterceptors(interceptor) {
-    if (typeof interceptor.runWhen === 'function' && interceptor.runWhen(config) === false) {
-      return;
+  /**
+   * Dispatch a request
+   *
+   * @param {String|Object} configOrUrl The config specific for this request (merged with this.defaults)
+   * @param {?Object} config
+   *
+   * @returns {Promise} The Promise to be fulfilled
+   */
+  request(configOrUrl, config) {
+    /*eslint no-param-reassign:0*/
+    // Allow for axios('example/url'[, config]) a la fetch API
+    if (typeof configOrUrl === 'string') {
+      config = config || {};
+      config.url = configOrUrl;
+    } else {
+      config = configOrUrl || {};
     }
 
-    synchronousRequestInterceptors = synchronousRequestInterceptors && interceptor.synchronous;
+    config = mergeConfig(this.defaults, config);
 
-    requestInterceptorChain.unshift(interceptor.fulfilled, interceptor.rejected);
-  });
+    const transitional = config.transitional;
 
-  var responseInterceptorChain = [];
-  this.interceptors.response.forEach(function pushResponseInterceptors(interceptor) {
-    responseInterceptorChain.push(interceptor.fulfilled, interceptor.rejected);
-  });
+    if (transitional !== undefined) {
+      validator.assertOptions(transitional, {
+        silentJSONParsing: validators.transitional(validators.boolean),
+        forcedJSONParsing: validators.transitional(validators.boolean),
+        clarifyTimeoutError: validators.transitional(validators.boolean)
+      }, false);
+    }
 
-  var promise;
+    // Set config.method
+    config.method = (config.method || this.defaults.method || 'get').toLowerCase();
 
-  if (!synchronousRequestInterceptors) {
-    var chain = [dispatchRequest, undefined];
+    // Flatten headers
+    const defaultHeaders = config.headers && utils.merge(
+      config.headers.common,
+      config.headers[config.method]
+    );
 
-    Array.prototype.unshift.apply(chain, requestInterceptorChain);
-    chain = chain.concat(responseInterceptorChain);
+    defaultHeaders && utils.forEach(
+      ['delete', 'get', 'head', 'post', 'put', 'patch', 'common'],
+      function cleanHeaderConfig(method) {
+        delete config.headers[method];
+      }
+    );
 
-    promise = Promise.resolve(config);
-    while (chain.length) {
-      promise = promise.then(chain.shift(), chain.shift());
+    config.headers = new AxiosHeaders(config.headers, defaultHeaders);
+
+    // filter out skipped interceptors
+    const requestInterceptorChain = [];
+    let synchronousRequestInterceptors = true;
+    this.interceptors.request.forEach(function unshiftRequestInterceptors(interceptor) {
+      if (typeof interceptor.runWhen === 'function' && interceptor.runWhen(config) === false) {
+        return;
+      }
+
+      synchronousRequestInterceptors = synchronousRequestInterceptors && interceptor.synchronous;
+
+      requestInterceptorChain.unshift(interceptor.fulfilled, interceptor.rejected);
+    });
+
+    const responseInterceptorChain = [];
+    this.interceptors.response.forEach(function pushResponseInterceptors(interceptor) {
+      responseInterceptorChain.push(interceptor.fulfilled, interceptor.rejected);
+    });
+
+    let promise;
+    let i = 0;
+    let len;
+
+    if (!synchronousRequestInterceptors) {
+      const chain = [dispatchRequest.bind(this), undefined];
+      chain.unshift.apply(chain, requestInterceptorChain);
+      chain.push.apply(chain, responseInterceptorChain);
+      len = chain.length;
+
+      promise = Promise.resolve(config);
+
+      while (i < len) {
+        promise = promise.then(chain[i++], chain[i++]);
+      }
+
+      return promise;
+    }
+
+    len = requestInterceptorChain.length;
+
+    let newConfig = config;
+
+    i = 0;
+
+    while (i < len) {
+      const onFulfilled = requestInterceptorChain[i++];
+      const onRejected = requestInterceptorChain[i++];
+      try {
+        newConfig = onFulfilled(newConfig);
+      } catch (error) {
+        onRejected.call(this, error);
+        break;
+      }
+    }
+
+    try {
+      promise = dispatchRequest.call(this, newConfig);
+    } catch (error) {
+      return Promise.reject(error);
+    }
+
+    i = 0;
+    len = responseInterceptorChain.length;
+
+    while (i < len) {
+      promise = promise.then(responseInterceptorChain[i++], responseInterceptorChain[i++]);
     }
 
     return promise;
   }
 
-
-  var newConfig = config;
-  while (requestInterceptorChain.length) {
-    var onFulfilled = requestInterceptorChain.shift();
-    var onRejected = requestInterceptorChain.shift();
-    try {
-      newConfig = onFulfilled(newConfig);
-    } catch (error) {
-      onRejected(error);
-      break;
-    }
+  getUri(config) {
+    config = mergeConfig(this.defaults, config);
+    const fullPath = buildFullPath(config.baseURL, config.url);
+    return buildURL(fullPath, config.params, config.paramsSerializer);
   }
-
-  try {
-    promise = dispatchRequest(newConfig);
-  } catch (error) {
-    return Promise.reject(error);
-  }
-
-  while (responseInterceptorChain.length) {
-    promise = promise.then(responseInterceptorChain.shift(), responseInterceptorChain.shift());
-  }
-
-  return promise;
-};
-
-Axios.prototype.getUri = function getUri(config) {
-  config = mergeConfig(this.defaults, config);
-  var fullPath = buildFullPath(config.baseURL, config.url);
-  return buildURL(fullPath, config.params, config.paramsSerializer);
-};
+}
 
 // Provide aliases for supported request methods
 utils.forEach(['delete', 'get', 'head', 'options'], function forEachMethodNoData(method) {
   /*eslint func-names:0*/
   Axios.prototype[method] = function(url, config) {
     return this.request(mergeConfig(config || {}, {
-      method: method,
-      url: url,
+      method,
+      url,
       data: (config || {}).data
     }));
   };
@@ -147,12 +170,12 @@ utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
   function generateHTTPMethod(isForm) {
     return function httpMethod(url, data, config) {
       return this.request(mergeConfig(config || {}, {
-        method: method,
+        method,
         headers: isForm ? {
           'Content-Type': 'multipart/form-data'
         } : {},
-        url: url,
-        data: data
+        url,
+        data
       }));
     };
   }
@@ -162,4 +185,4 @@ utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
   Axios.prototype[method + 'Form'] = generateHTTPMethod(true);
 });
 
-module.exports = Axios;
+export default Axios;

lib/core/AxiosError.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var utils = require('../utils');
+import utils from '../utils.js';
 
 /**
  * Create an Error with the specified message, config, error code, request and response.
@@ -52,8 +52,8 @@ utils.inherits(AxiosError, Error, {
   }
 });
 
-var prototype = AxiosError.prototype;
-var descriptors = {};
+const prototype = AxiosError.prototype;
+const descriptors = {};
 
 [
   'ERR_BAD_OPTION_VALUE',
@@ -69,7 +69,7 @@ var descriptors = {};
   'ERR_NOT_SUPPORT',
   'ERR_INVALID_URL'
 // eslint-disable-next-line func-names
-].forEach(function(code) {
+].forEach(code => {
   descriptors[code] = {value: code};
 });
 
@@ -77,11 +77,13 @@ Object.defineProperties(AxiosError, descriptors);
 Object.defineProperty(prototype, 'isAxiosError', {value: true});
 
 // eslint-disable-next-line func-names
-AxiosError.from = function(error, code, config, request, response, customProps) {
-  var axiosError = Object.create(prototype);
+AxiosError.from = (error, code, config, request, response, customProps) => {
+  const axiosError = Object.create(prototype);
 
   utils.toFlatObject(error, axiosError, function filter(obj) {
     return obj !== Error.prototype;
+  }, prop => {
+    return prop !== 'isAxiosError';
   });
 
   AxiosError.call(axiosError, error.message, code, config, request, response);
@@ -95,4 +97,4 @@ AxiosError.from = function(error, code, config, request, response, customProps)
   return axiosError;
 };
 
-module.exports = AxiosError;
+export default AxiosError;

lib/core/AxiosHeaders.js

@@ -0,0 +1,274 @@
+'use strict';
+
+import utils from '../utils.js';
+import parseHeaders from '../helpers/parseHeaders.js';
+
+const $internals = Symbol('internals');
+const $defaults = Symbol('defaults');
+
+function normalizeHeader(header) {
+  return header && String(header).trim().toLowerCase();
+}
+
+function normalizeValue(value) {
+  if (value === false || value == null) {
+    return value;
+  }
+
+  return String(value);
+}
+
+function parseTokens(str) {
+  const tokens = Object.create(null);
+  const tokensRE = /([^\s,;=]+)\s*(?:=\s*([^,;]+))?/g;
+  let match;
+
+  while ((match = tokensRE.exec(str))) {
+    tokens[match[1]] = match[2];
+  }
+
+  return tokens;
+}
+
+function matchHeaderValue(context, value, header, filter) {
+  if (utils.isFunction(filter)) {
+    return filter.call(this, value, header);
+  }
+
+  if (!utils.isString(value)) return;
+
+  if (utils.isString(filter)) {
+    return value.indexOf(filter) !== -1;
+  }
+
+  if (utils.isRegExp(filter)) {
+    return filter.test(value);
+  }
+}
+
+function formatHeader(header) {
+  return header.trim()
+    .toLowerCase().replace(/([a-z\d])(\w*)/g, (w, char, str) => {
+      return char.toUpperCase() + str;
+    });
+}
+
+function buildAccessors(obj, header) {
+  const accessorName = utils.toCamelCase(' ' + header);
+
+  ['get', 'set', 'has'].forEach(methodName => {
+    Object.defineProperty(obj, methodName + accessorName, {
+      value: function(arg1, arg2, arg3) {
+        return this[methodName].call(this, header, arg1, arg2, arg3);
+      },
+      configurable: true
+    });
+  });
+}
+
+function findKey(obj, key) {
+  key = key.toLowerCase();
+  const keys = Object.keys(obj);
+  let i = keys.length;
+  let _key;
+  while (i-- > 0) {
+    _key = keys[i];
+    if (key === _key.toLowerCase()) {
+      return _key;
+    }
+  }
+  return null;
+}
+
+function AxiosHeaders(headers, defaults) {
+  headers && this.set(headers);
+  this[$defaults] = defaults || null;
+}
+
+Object.assign(AxiosHeaders.prototype, {
+  set: function(header, valueOrRewrite, rewrite) {
+    const self = this;
+
+    function setHeader(_value, _header, _rewrite) {
+      const lHeader = normalizeHeader(_header);
+
+      if (!lHeader) {
+        throw new Error('header name must be a non-empty string');
+      }
+
+      const key = findKey(self, lHeader);
+
+      if (key && _rewrite !== true && (self[key] === false || _rewrite === false)) {
+        return;
+      }
+
+      if (utils.isArray(_value)) {
+        _value = _value.map(normalizeValue);
+      } else {
+        _value = normalizeValue(_value);
+      }
+
+      self[key || _header] = _value;
+    }
+
+    if (utils.isPlainObject(header)) {
+      utils.forEach(header, (_value, _header) => {
+        setHeader(_value, _header, valueOrRewrite);
+      });
+    } else {
+      setHeader(valueOrRewrite, header, rewrite);
+    }
+
+    return this;
+  },
+
+  get: function(header, parser) {
+    header = normalizeHeader(header);
+
+    if (!header) return undefined;
+
+    const key = findKey(this, header);
+
+    if (key) {
+      const value = this[key];
+
+      if (!parser) {
+        return value;
+      }
+
+      if (parser === true) {
+        return parseTokens(value);
+      }
+
+      if (utils.isFunction(parser)) {
+        return parser.call(this, value, key);
+      }
+
+      if (utils.isRegExp(parser)) {
+        return parser.exec(value);
+      }
+
+      throw new TypeError('parser must be boolean|regexp|function');
+    }
+  },
+
+  has: function(header, matcher) {
+    header = normalizeHeader(header);
+
+    if (header) {
+      const key = findKey(this, header);
+
+      return !!(key && (!matcher || matchHeaderValue(this, this[key], key, matcher)));
+    }
+
+    return false;
+  },
+
+  delete: function(header, matcher) {
+    const self = this;
+    let deleted = false;
+
+    function deleteHeader(_header) {
+      _header = normalizeHeader(_header);
+
+      if (_header) {
+        const key = findKey(self, _header);
+
+        if (key && (!matcher || matchHeaderValue(self, self[key], key, matcher))) {
+          delete self[key];
+
+          deleted = true;
+        }
+      }
+    }
+
+    if (utils.isArray(header)) {
+      header.forEach(deleteHeader);
+    } else {
+      deleteHeader(header);
+    }
+
+    return deleted;
+  },
+
+  clear: function() {
+    return Object.keys(this).forEach(this.delete.bind(this));
+  },
+
+  normalize: function(format) {
+    const self = this;
+    const headers = {};
+
+    utils.forEach(this, (value, header) => {
+      const key = findKey(headers, header);
+
+      if (key) {
+        self[key] = normalizeValue(value);
+        delete self[header];
+        return;
+      }
+
+      const normalized = format ? formatHeader(header) : String(header).trim();
+
+      if (normalized !== header) {
+        delete self[header];
+      }
+
+      self[normalized] = normalizeValue(value);
+
+      headers[normalized] = true;
+    });
+
+    return this;
+  },
+
+  toJSON: function() {
+    const obj = Object.create(null);
+
+    utils.forEach(Object.assign({}, this[$defaults] || null, this),
+      (value, header) => {
+        if (value == null || value === false) return;
+        obj[header] = utils.isArray(value) ? value.join(', ') : value;
+      });
+
+    return obj;
+  }
+});
+
+Object.assign(AxiosHeaders, {
+  from: function(thing) {
+    if (utils.isString(thing)) {
+      return new this(parseHeaders(thing));
+    }
+    return thing instanceof this ? thing : new this(thing);
+  },
+
+  accessor: function(header) {
+    const internals = this[$internals] = (this[$internals] = {
+      accessors: {}
+    });
+
+    const accessors = internals.accessors;
+    const prototype = this.prototype;
+
+    function defineAccessor(_header) {
+      const lHeader = normalizeHeader(_header);
+
+      if (!accessors[lHeader]) {
+        buildAccessors(prototype, _header);
+        accessors[lHeader] = true;
+      }
+    }
+
+    utils.isArray(header) ? header.forEach(defineAccessor) : defineAccessor(header);
+
+    return this;
+  }
+});
+
+AxiosHeaders.accessor(['Content-Type', 'Content-Length', 'Accept', 'Accept-Encoding', 'User-Agent']);
+
+utils.freezeMethods(AxiosHeaders.prototype);
+utils.freezeMethods(AxiosHeaders);
+
+export default AxiosHeaders;

lib/core/InterceptorManager.js

@@ -1,69 +1,71 @@
 'use strict';
 
-var utils = require('./../utils');
+import utils from './../utils.js';
 
-function InterceptorManager() {
-  this.handlers = [];
-}
-
-/**
- * Add a new interceptor to the stack
- *
- * @param {Function} fulfilled The function to handle `then` for a `Promise`
- * @param {Function} rejected The function to handle `reject` for a `Promise`
- *
- * @return {Number} An ID used to remove interceptor later
- */
-InterceptorManager.prototype.use = function use(fulfilled, rejected, options) {
-  this.handlers.push({
-    fulfilled: fulfilled,
-    rejected: rejected,
-    synchronous: options ? options.synchronous : false,
-    runWhen: options ? options.runWhen : null
-  });
-  return this.handlers.length - 1;
-};
-
-/**
- * Remove an interceptor from the stack
- *
- * @param {Number} id The ID that was returned by `use`
- *
- * @returns {Boolean} `true` if the interceptor was removed, `false` otherwise
- */
-InterceptorManager.prototype.eject = function eject(id) {
-  if (this.handlers[id]) {
-    this.handlers[id] = null;
-  }
-};
-
-/**
- * Clear all interceptors from the stack
- *
- * @returns {void}
- */
-InterceptorManager.prototype.clear = function clear() {
-  if (this.handlers) {
+class InterceptorManager {
+  constructor() {
     this.handlers = [];
   }
-};
 
-/**
- * Iterate over all the registered interceptors
- *
- * This method is particularly useful for skipping over any
- * interceptors that may have become `null` calling `eject`.
- *
- * @param {Function} fn The function to call for each interceptor
- *
- * @returns {void}
- */
-InterceptorManager.prototype.forEach = function forEach(fn) {
-  utils.forEach(this.handlers, function forEachHandler(h) {
-    if (h !== null) {
-      fn(h);
+  /**
+   * Add a new interceptor to the stack
+   *
+   * @param {Function} fulfilled The function to handle `then` for a `Promise`
+   * @param {Function} rejected The function to handle `reject` for a `Promise`
+   *
+   * @return {Number} An ID used to remove interceptor later
+   */
+  use(fulfilled, rejected, options) {
+    this.handlers.push({
+      fulfilled,
+      rejected,
+      synchronous: options ? options.synchronous : false,
+      runWhen: options ? options.runWhen : null
+    });
+    return this.handlers.length - 1;
+  }
+
+  /**
+   * Remove an interceptor from the stack
+   *
+   * @param {Number} id The ID that was returned by `use`
+   *
+   * @returns {Boolean} `true` if the interceptor was removed, `false` otherwise
+   */
+  eject(id) {
+    if (this.handlers[id]) {
+      this.handlers[id] = null;
     }
-  });
-};
+  }
 
-module.exports = InterceptorManager;
+  /**
+   * Clear all interceptors from the stack
+   *
+   * @returns {void}
+   */
+  clear() {
+    if (this.handlers) {
+      this.handlers = [];
+    }
+  }
+
+  /**
+   * Iterate over all the registered interceptors
+   *
+   * This method is particularly useful for skipping over any
+   * interceptors that may have become `null` calling `eject`.
+   *
+   * @param {Function} fn The function to call for each interceptor
+   *
+   * @returns {void}
+   */
+  forEach(fn) {
+    utils.forEach(this.handlers, function forEachHandler(h) {
+      if (h !== null) {
+        fn(h);
+      }
+    });
+  }
+}
+
+export default InterceptorManager;

lib/core/buildFullPath.js

@@ -1,7 +1,7 @@
 'use strict';
 
-var isAbsoluteURL = require('../helpers/isAbsoluteURL');
-var combineURLs = require('../helpers/combineURLs');
+import isAbsoluteURL from '../helpers/isAbsoluteURL.js';
+import combineURLs from '../helpers/combineURLs.js';
 
 /**
  * Creates a new URL by combining the baseURL with the requestedURL,
@@ -13,9 +13,9 @@ var combineURLs = require('../helpers/combineURLs');
  *
  * @returns {string} The combined full path
  */
-module.exports = function buildFullPath(baseURL, requestedURL) {
+export default function buildFullPath(baseURL, requestedURL) {
   if (baseURL && !isAbsoluteURL(requestedURL)) {
     return combineURLs(baseURL, requestedURL);
   }
   return requestedURL;
-};
+}

lib/core/dispatchRequest.js

@@ -1,11 +1,10 @@
 'use strict';
 
-var utils = require('./../utils');
-var transformData = require('./transformData');
-var isCancel = require('../cancel/isCancel');
-var defaults = require('../defaults');
-var CanceledError = require('../cancel/CanceledError');
-var normalizeHeaderName = require('../helpers/normalizeHeaderName');
+import transformData from './transformData.js';
+import isCancel from '../cancel/isCancel.js';
+import defaults from '../defaults/index.js';
+import CanceledError from '../cancel/CanceledError.js';
+import AxiosHeaders from '../core/AxiosHeaders.js';
 
 /**
  * Throws a `CanceledError` if cancellation has been requested.
@@ -31,39 +30,18 @@ function throwIfCancellationRequested(config) {
  *
  * @returns {Promise} The Promise to be fulfilled
  */
-module.exports = function dispatchRequest(config) {
+export default function dispatchRequest(config) {
   throwIfCancellationRequested(config);
 
-  // Ensure headers exist
-  config.headers = config.headers || {};
+  config.headers = AxiosHeaders.from(config.headers);
 
   // Transform request data
   config.data = transformData.call(
     config,
-    config.data,
-    config.headers,
-    null,
     config.transformRequest
   );
 
-  normalizeHeaderName(config.headers, 'Accept');
-  normalizeHeaderName(config.headers, 'Content-Type');
-
-  // Flatten headers
-  config.headers = utils.merge(
-    config.headers.common || {},
-    config.headers[config.method] || {},
-    config.headers
-  );
-
-  utils.forEach(
-    ['delete', 'get', 'head', 'post', 'put', 'patch', 'common'],
-    function cleanHeaderConfig(method) {
-      delete config.headers[method];
-    }
-  );
-
-  var adapter = config.adapter || defaults.adapter;
+  const adapter = config.adapter || defaults.adapter;
 
   return adapter(config).then(function onAdapterResolution(response) {
     throwIfCancellationRequested(config);
@@ -71,12 +49,12 @@ module.exports = function dispatchRequest(config) {
     // Transform response data
     response.data = transformData.call(
       config,
-      response.data,
-      response.headers,
-      response.status,
-      config.transformResponse
+      config.transformResponse,
+      response
     );
 
+    response.headers = AxiosHeaders.from(response.headers);
+
     return response;
   }, function onAdapterRejection(reason) {
     if (!isCancel(reason)) {
@@ -86,14 +64,13 @@ module.exports = function dispatchRequest(config) {
       if (reason && reason.response) {
         reason.response.data = transformData.call(
           config,
-          reason.response.data,
-          reason.response.headers,
-          reason.response.status,
-          config.transformResponse
+          config.transformResponse,
+          reason.response
         );
+        reason.response.headers = AxiosHeaders.from(reason.response.headers);
       }
     }
 
     return Promise.reject(reason);
   });
-};
+}

lib/core/mergeConfig.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var utils = require('../utils');
+import utils from '../utils.js';
 
 /**
  * Config-specific merge-function which creates a new config-object
@@ -11,10 +11,10 @@ var utils = require('../utils');
  *
  * @returns {Object} New object resulting from merging config2 to config1
  */
-module.exports = function mergeConfig(config1, config2) {
+export default function mergeConfig(config1, config2) {
   // eslint-disable-next-line no-param-reassign
   config2 = config2 || {};
-  var config = {};
+  const config = {};
 
   function getMergedValue(target, source) {
     if (utils.isPlainObject(target) && utils.isPlainObject(source)) {
@@ -61,7 +61,7 @@ module.exports = function mergeConfig(config1, config2) {
     }
   }
 
-  var mergeMap = {
+  const mergeMap = {
     'url': valueFromConfig2,
     'method': valueFromConfig2,
     'data': valueFromConfig2,
@@ -92,10 +92,10 @@ module.exports = function mergeConfig(config1, config2) {
   };
 
   utils.forEach(Object.keys(config1).concat(Object.keys(config2)), function computeConfigValue(prop) {
-    var merge = mergeMap[prop] || mergeDeepProperties;
-    var configValue = merge(prop);
+    const merge = mergeMap[prop] || mergeDeepProperties;
+    const configValue = merge(prop);
     (utils.isUndefined(configValue) && merge !== mergeDirectKeys) || (config[prop] = configValue);
   });
 
   return config;
-};
+}

lib/core/settle.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var AxiosError = require('./AxiosError');
+import AxiosError from './AxiosError.js';
 
 /**
  * Resolve or reject a Promise based on response status.
@@ -11,8 +11,8 @@ var AxiosError = require('./AxiosError');
  *
  * @returns {object} The response.
  */
-module.exports = function settle(resolve, reject, response) {
-  var validateStatus = response.config.validateStatus;
+export default function settle(resolve, reject, response) {
+  const validateStatus = response.config.validateStatus;
   if (!response.status || !validateStatus || validateStatus(response.status)) {
     resolve(response);
   } else {
@@ -24,4 +24,4 @@ module.exports = function settle(resolve, reject, response) {
       response
     ));
   }
-};
+}

lib/core/transformData.js

@@ -1,24 +1,28 @@
 'use strict';
 
-var utils = require('./../utils');
-var defaults = require('../defaults');
+import utils from './../utils.js';
+import defaults from '../defaults/index.js';
+import AxiosHeaders from '../core/AxiosHeaders.js';
 
 /**
  * Transform the data for a request or a response
  *
- * @param {Object|String} data The data to be transformed
- * @param {Array} headers The headers for the request or response
- * @param {Number} status HTTP status code
  * @param {Array|Function} fns A single function or Array of functions
+ * @param {?Object} response The response object
  *
  * @returns {*} The resulting transformed data
  */
-module.exports = function transformData(data, headers, status, fns) {
-  var context = this || defaults;
-  /*eslint no-param-reassign:0*/
+export default function transformData(fns, response) {
+  const config = this || defaults;
+  const context = response || config;
+  const headers = AxiosHeaders.from(context.headers);
+  let data = context.data;
+
   utils.forEach(fns, function transform(fn) {
-    data = fn.call(context, data, headers, status);
+    data = fn.call(config, data, headers.normalize(), response ? response.status : undefined);
   });
 
+  headers.normalize();
+
   return data;
-};
+}