Added FormData automatic serialization section to Readme.md;

README.md

@@ -22,7 +22,7 @@ Promise based HTTP client for the browser and node.js
   - [Example](#example)
   - [Axios API](#axios-api)
   - [Request method aliases](#request-method-aliases)
-  - [Concurrency (Deprecated)](#concurrency-deprecated)
+  - [Concurrency 👎](#concurrency-deprecated)
   - [Creating an instance](#creating-an-instance)
   - [Instance methods](#instance-methods)
   - [Request Config](#request-config)
@@ -35,11 +35,15 @@ Promise based HTTP client for the browser and node.js
     - [Multiple Interceptors](#multiple-interceptors)
   - [Handling Errors](#handling-errors)
   - [Cancellation](#cancellation)
+    - [AbortController](#abortcontroller)
+    - [CancelToken 👎](#canceltoken-deprecated)
   - [Using application/x-www-form-urlencoded format](#using-applicationx-www-form-urlencoded-format)
     - [Browser](#browser)
     - [Node.js](#nodejs)
       - [Query string](#query-string)
       - [Form data](#form-data)
+        - [Automatic serialization](#-automatic-serialization)
+        - [Manual FormData passing](#manual-formdata-passing)
   - [Semver](#semver)
   - [Promises](#promises)
   - [TypeScript](#typescript)
@@ -482,6 +486,11 @@ These are the available config options for making requests. Only the `url` is re
 
     // throw ETIMEDOUT error instead of generic ECONNABORTED on request timeouts
     clarifyTimeoutError: false,
+  },
+
+  env: {
+    // The FormData class to be used to automatically serialize the payload into a FormData object
+    FormData: window?.FormData || global?.FormData
   }
 }
 ```
@@ -706,10 +715,30 @@ axios.get('/user/12345')
 
 ## Cancellation
 
-You can cancel a request using a *cancel token*.
+### AbortController
+
+Starting from `v0.22.0` Axios supports AbortController to cancel requests in fetch API way:
+
+```js
+const controller = new AbortController();
+
+axios.get('/foo/bar', {
+   signal: controller.signal
+}).then(function(response) {
+   //...
+});
+// cancel the request
+controller.abort()
+```
+
+### CancelToken `👎deprecated`
+
+You can also cancel a request using a *CancelToken*.
 
 > The axios cancel token API is based on the withdrawn [cancelable promises proposal](https://github.com/tc39/proposal-cancelable-promises).
 
+> This API is deprecated since v0.22.0 and shouldn't be used in new projects
+
 You can create a cancel token using the `CancelToken.source` factory as shown below:
 
 ```js
@@ -753,22 +782,11 @@ axios.get('/user/12345', {
 cancel();
 ```
 
-Axios supports AbortController to abort requests in [`fetch API`](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API#aborting_a_fetch) way:
-```js
-const controller = new AbortController();
-
-axios.get('/foo/bar', {
-   signal: controller.signal
-}).then(function(response) {
-   //...
-});
-// cancel the request
-controller.abort()
-```
-
 > Note: you can cancel several requests with the same cancel token/abort controller.
 > If a cancellation token is already cancelled at the moment of starting an Axios request, then the request is cancelled immediately, without any attempts to make real request.
 
+> During the transition period, you can use both cancellation APIs, even for the same request:
+
 ## Using application/x-www-form-urlencoded format
 
 By default, axios serializes JavaScript objects to `JSON`. To send data in the `application/x-www-form-urlencoded` format instead, you can use one of the following options.
@@ -833,6 +851,46 @@ The `qs` library is preferable if you need to stringify nested objects, as the `
 
 #### Form data
 
+##### 🆕 Automatic serialization
+
+Starting from `v0.26.0`, Axios supports automatic object serialization to a FormData object if the request `Content-Type` 
+header is set to `multipart/form-data`.
+
+The following request will submit the data object as a form:
+
+```js
+import axios from 'axios';
+
+axios.post('https://postman-echo.com/post', {x: 1}, {
+  headers: {
+    'Content-Type': 'multipart/form-data'
+  }
+}).then(({data})=> console.log(data));
+```
+
+This will only work if the FormData class is available in the environment as a global variable.
+For `node.js` you have to import FormData polyfill ([`form-data`](https://github.com/form-data/form-data)) manually and set it as an `env` section config variable..
+
+```js
+const axios= require('axios');
+var FormData = require('form-data');
+
+// OR
+// axios.defaults.env.FormData= FormData;
+
+axios.post('https://postman-echo.com/post', {x: 1, buf: new Buffer(10)}, {
+  headers: {
+    'Content-Type': 'multipart/form-data'
+  },
+
+  env: {  // OR
+    FormData
+  }
+}).then(({data})=> console.log(data));
+```
+
+##### Manual FormData passing
+
 In node.js, you can use the [`form-data`](https://github.com/form-data/form-data) library as follows:
 
 ```js
@@ -843,18 +901,7 @@ form.append('my_field', 'my value');
 form.append('my_buffer', new Buffer(10));
 form.append('my_file', fs.createReadStream('/foo/bar.jpg'));
 
-axios.post('https://example.com', form, { headers: form.getHeaders() })
-```
-
-Alternatively, use an interceptor:
-
-```js
-axios.interceptors.request.use(config => {
-  if (config.data instanceof FormData) {
-    Object.assign(config.headers, config.data.getHeaders());
-  }
-  return config;
-});
+axios.post('https://example.com', form)
 ```
 
 ## Semver