Improved FormData support;

README.md

@@ -23,7 +23,7 @@ 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)
@@ -36,11 +36,15 @@ 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)
@@ -483,6 +487,11 @@ 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
   }
 }
 ```
@@ -707,10 +716,30 @@ 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 The axios cancel token API is based on the withdrawn [cancelable promises proposal](https://github.com/tc39/proposal-cancelable-promises).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
@@ -754,22 +783,11 @@ 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.
@@ -829,11 +847,75 @@ axios.post('http://something.com/', params.toString());
 
 You can also use the [`qs`](https://github.com/ljharb/qs) library.
 
-###### NOTE
-The `qs` library is preferable if you need to stringify nested objects, as the `querystring` method has known issues with that use case (https://github.com/nodejs/node-v0.x-archive/issues/1665).
+> NOTE: 
+> The `qs` library is preferable if you need to stringify nested objects, as the `querystring` method has [known issues](https://github.com/nodejs/node-v0.x-archive/issues/1665) with that use case.
 
 #### Form data
 
+##### 🆕 Automatic serialization
+
+Starting from `v0.27.0`, 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 in a FormData format (Browser & Node.js):
+
+```js
+import axios from 'axios';
+
+axios.post('https://httpbin.org/post', {x: 1}, {
+  headers: {
+    'Content-Type': 'multipart/form-data'
+  }
+}).then(({data})=> console.log(data));
+```
+
+In the `node.js` build, the ([`form-data`](https://github.com/form-data/form-data)) polyfill is used by default.
+
+You can overload the FormData class by setting the `env.FormData` config variable,
+but you probably won't need it in most cases:
+
+```js
+const axios= require('axios');
+var FormData = require('form-data');
+
+axios.post('https://httpbin.org/post', {x: 1, buf: new Buffer(10)}, {
+  headers: {
+    'Content-Type': 'multipart/form-data'
+  }
+}).then(({data})=> console.log(data));
+```
+
+Axios FormData serializer supports some special endings to perform the following operations:
+
+- `{}` - serialize the value with JSON.stringify
+- `[]` - unwrap the array like object as separate fields with the same key 
+
+```js
+const axios= require('axios');
+
+axios.post('https://httpbin.org/post', {
+  'myObj{}': {x: 1, s: "foo"},
+  'files[]': document.querySelector('#fileInput').files 
+}, {
+  headers: {
+    'Content-Type': 'multipart/form-data'
+  }
+}).then(({data})=> console.log(data));
+```
+
+Axios supports the following shortcut methods: `postForm`, `putForm`, `patchForm`
+which are just the corresponding http methods with a header preset: `Content-Type`: `multipart/form-data`.
+
+FileList object can be passed directly:
+
+```js
+await axios.postForm('https://httpbin.org/post', document.querySelector('#fileInput').files)
+```
+
+All files will be sent with the same field names: `files[]`;
+
+##### Manual FormData passing
+
 In node.js, you can use the [`form-data`](https://github.com/form-data/form-data) library as follows:
 
 ```js
@@ -844,18 +926,7 @@ 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

index.d.ts

@@ -107,6 +107,9 @@ export interface AxiosRequestConfig<D = any> {
   transitional?: TransitionalOptions;
   signal?: AbortSignal;
   insecureHTTPParser?: boolean;
+  env?: {
+    FormData?: new (...args: any[]) => object;
+  };
 }
 
 export interface HeadersDefaults {
@@ -197,6 +200,9 @@ export class Axios {
   post<T = any, R = AxiosResponse<T>, D = any>(url: string, data?: D, config?: AxiosRequestConfig<D>): Promise<R>;
   put<T = any, R = AxiosResponse<T>, D = any>(url: string, data?: D, config?: AxiosRequestConfig<D>): Promise<R>;
   patch<T = any, R = AxiosResponse<T>, D = any>(url: string, data?: D, config?: AxiosRequestConfig<D>): Promise<R>;
+  postForm<T = any, R = AxiosResponse<T>, D = any>(url: string, data?: D, config?: AxiosRequestConfig<D>): Promise<R>;
+  putForm<T = any, R = AxiosResponse<T>, D = any>(url: string, data?: D, config?: AxiosRequestConfig<D>): Promise<R>;
+  patchForm<T = any, R = AxiosResponse<T>, D = any>(url: string, data?: D, config?: AxiosRequestConfig<D>): Promise<R>;
 }
 
 export interface AxiosInstance extends Axios {

lib/adapters/http.js

@@ -87,7 +87,10 @@ module.exports = function httpAdapter(config) {
       headers['User-Agent'] = 'axios/' + VERSION;
     }
 
-    if (data && !utils.isStream(data)) {
+    // support for https://www.npmjs.com/package/form-data api
+    if (utils.isFormData(data) && utils.isFunction(data.getHeaders)) {
+      Object.assign(headers, data.getHeaders());
+    } else if (data && !utils.isStream(data)) {
       if (Buffer.isBuffer(data)) {
         // Nothing to do...
       } else if (utils.isArrayBuffer(data)) {

lib/axios.js

@@ -41,6 +41,7 @@ axios.Cancel = require('./cancel/Cancel');
 axios.CancelToken = require('./cancel/CancelToken');
 axios.isCancel = require('./cancel/isCancel');
 axios.VERSION = require('./env/data').version;
+axios.toFormData = require('./helpers/toFormData');
 
 // Expose all/spread
 axios.all = function all(promises) {

lib/core/Axios.js

@@ -136,13 +136,23 @@ utils.forEach(['delete', 'get', 'head', 'options'], function forEachMethodNoData
 
 utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
   /*eslint func-names:0*/
-  Axios.prototype[method] = function(url, data, config) {
-    return this.request(mergeConfig(config || {}, {
-      method: method,
-      url: url,
-      data: data
-    }));
-  };
+
+  function generateHTTPMethod(isForm) {
+    return function httpMethod(url, data, config) {
+      return this.request(mergeConfig(config || {}, {
+        method: method,
+        headers: isForm ? {
+          'Content-Type': 'multipart/form-data'
+        } : {},
+        url: url,
+        data: data
+      }));
+    };
+  }
+
+  Axios.prototype[method] = generateHTTPMethod();
+
+  Axios.prototype[method + 'Form'] = generateHTTPMethod(true);
 });
 
 module.exports = Axios;

lib/defaults.js

@@ -3,6 +3,7 @@
 var utils = require('./utils');
 var normalizeHeaderName = require('./helpers/normalizeHeaderName');
 var enhanceError = require('./core/enhanceError');
+var toFormData = require('./helpers/toFormData');
 
 var DEFAULT_CONTENT_TYPE = {
   'Content-Type': 'application/x-www-form-urlencoded'
@@ -71,10 +72,20 @@ var defaults = {
       setContentTypeIfUnset(headers, 'application/x-www-form-urlencoded;charset=utf-8');
       return data.toString();
     }
-    if (utils.isObject(data) || (headers && headers['Content-Type'] === 'application/json')) {
+
+    var isObjectPayload = utils.isObject(data);
+    var contentType = headers && headers['Content-Type'];
+
+    var isFileList;
+
+    if ((isFileList = utils.isFileList(data)) || (isObjectPayload && contentType === 'multipart/form-data')) {
+      var _FormData = this.env && this.env.FormData;
+      return toFormData(isFileList ? {'files[]': data} : data, _FormData && new _FormData());
+    } else if (isObjectPayload || contentType === 'application/json') {
       setContentTypeIfUnset(headers, 'application/json');
       return stringifySafely(data);
     }
+
     return data;
   }],
 
@@ -112,6 +123,10 @@ var defaults = {
   maxContentLength: -1,
   maxBodyLength: -1,
 
+  env: {
+    FormData: require('./defaults/env/FormData')
+  },
+
   validateStatus: function validateStatus(status) {
     return status >= 200 && status < 300;
   },

lib/defaults/env/FormData.js

@@ -0,0 +1,2 @@
+// eslint-disable-next-line strict
+module.exports = require('form-data');

lib/helpers/null.js

@@ -0,0 +1,2 @@
+// eslint-disable-next-line strict
+module.exports = null;