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/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;