feat(Body): Added support for BodyMixin.formData() and constructing…

… bodies with FormData (#1314)

Added support for body toFormData

@types/index.d.ts

@@ -103,6 +103,7 @@ export type BodyInit =
 	| Blob
 	| Buffer
 	| URLSearchParams
+	| FormData
 	| NodeJS.ReadableStream
 	| string;
 declare class BodyMixin {
@@ -117,6 +118,7 @@ declare class BodyMixin {
  	*/
 	buffer(): Promise<Buffer>;
 	arrayBuffer(): Promise<ArrayBuffer>;
+	formData(): Promise<FormData>;
 	blob(): Promise<Blob>;
 	json(): Promise<unknown>;
 	text(): Promise<string>;

README.md

@@ -731,6 +731,8 @@ A boolean property for if this body has been consumed. Per the specs, a consumed
 
 #### body.arrayBuffer()
 
+#### body.formData()
+
 #### body.blob()
 
 #### body.json()
@@ -743,14 +745,6 @@ A boolean property for if this body has been consumed. Per the specs, a consumed
 
 Consume the body and return a promise that will resolve to one of these formats.
 
-#### body.buffer()
-
-<small>_(node-fetch extension)_</small>
-
-- Returns: `Promise<Buffer>`
-
-Consume the body and return a promise that will resolve to a Buffer.
-
 <a id="class-fetcherror"></a>
 
 ### Class: FetchError

docs/CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## unreleased
 
 - other: Deprecated/Discourage [form-data](https://www.npmjs.com/package/form-data) and `body.buffer()` (#1212)
+- feat: Add `Body#formData()` (#1314)
 - fix: Normalize `Body.body` into a `node:stream` (#924)
 - fix: Pass url string to `http.request` for parsing IPv6 urls (#1268)
 - fix: Throw error when constructing Request with urls including basic auth (#1268)

package.json

@@ -55,14 +55,15 @@
     "coveralls": "^3.1.0",
     "delay": "^5.0.0",
     "form-data": "^4.0.0",
-    "formdata-node": "^3.5.4",
+    "formdata-node": "^4.2.4",
     "mocha": "^9.1.3",
     "p-timeout": "^5.0.0",
     "tsd": "^0.14.0",
     "xo": "^0.39.1"
   },
   "dependencies": {
     "data-uri-to-buffer": "^4.0.0",
+    "formdata-polyfill": "^4.0.10",
     "fetch-blob": "^3.1.2"
   },
   "tsd": {
@@ -91,6 +92,7 @@
       "unicorn/numeric-separators-style": 0,
       "unicorn/explicit-length-check": 0,
       "capitalized-comments": 0,
+      "node/no-unsupported-features/es-syntax": 0,
       "@typescript-eslint/member-ordering": 0
     },
     "overrides": [

src/body.js

@@ -9,11 +9,11 @@ import Stream, {PassThrough} from 'node:stream';
 import {types, deprecate} from 'node:util';
 
 import Blob from 'fetch-blob';
+import {FormData, formDataToBlob} from 'formdata-polyfill/esm.min.js';
 
 import {FetchError} from './errors/fetch-error.js';
 import {FetchBaseError} from './errors/base.js';
-import {formDataIterator, getBoundary, getFormDataLength} from './utils/form-data.js';
-import {isBlob, isURLSearchParameters, isFormData} from './utils/is.js';
+import {isBlob, isURLSearchParameters} from './utils/is.js';
 
 const INTERNALS = Symbol('Body internals');
 
@@ -50,10 +50,10 @@ export default class Body {
 			body = Buffer.from(body.buffer, body.byteOffset, body.byteLength);
 		} else if (body instanceof Stream) {
 			// Body is stream
-		} else if (isFormData(body)) {
-			// Body is an instance of formdata-node
-			boundary = `nodefetchformdataboundary${getBoundary()}`;
-			body = Stream.Readable.from(formDataIterator(body, boundary));
+		} else if (body instanceof FormData) {
+			// Body is FormData
+			body = formDataToBlob(body);
+			boundary = body.type.split('=')[1];
 		} else {
 			// None of the above
 			// coerce to string then buffer
@@ -105,6 +105,24 @@ export default class Body {
 		return buffer.slice(byteOffset, byteOffset + byteLength);
 	}
 
+	async formData() {
+		const ct = this.headers.get('content-type');
+
+		if (ct.startsWith('application/x-www-form-urlencoded')) {
+			const formData = new FormData();
+			const parameters = new URLSearchParams(await this.text());
+
+			for (const [name, value] of parameters) {
+				formData.append(name, value);
+			}
+
+			return formData;
+		}
+
+		const {toFormData} = await import('./utils/multipart-parser.js');
+		return toFormData(this.body, ct);
+	}
+
 	/**
 	 * Return raw response as Blob
 	 *
@@ -302,7 +320,7 @@ export const extractContentType = (body, request) => {
 		return null;
 	}
 
-	if (isFormData(body)) {
+	if (body instanceof FormData) {
 		return `multipart/form-data; boundary=${request[INTERNALS].boundary}`;
 	}
 
@@ -352,11 +370,6 @@ export const getTotalBytes = request => {
 		return body.hasKnownLength && body.hasKnownLength() ? body.getLengthSync() : null;
 	}
 
-	// Body is a spec-compliant FormData
-	if (isFormData(body)) {
-		return getFormDataLength(request[INTERNALS].boundary);
-	}
-
 	// Body is stream
 	return null;
 };

src/response.js

@@ -29,7 +29,7 @@ export default class Response extends Body {
 		const headers = new Headers(options.headers);
 
 		if (body !== null && !headers.has('Content-Type')) {
-			const contentType = extractContentType(body);
+			const contentType = extractContentType(body, this);
 			if (contentType) {
 				headers.append('Content-Type', contentType);
 			}

src/utils/is.js

@@ -9,8 +9,7 @@ const NAME = Symbol.toStringTag;
 /**
  * Check if `obj` is a URLSearchParams object
  * ref: https://github.com/node-fetch/node-fetch/issues/296#issuecomment-307598143
- *
- * @param  {*} obj
+ * @param {*} object - Object to check for
  * @return {boolean}
  */
 export const isURLSearchParameters = object => {
@@ -29,8 +28,7 @@ export const isURLSearchParameters = object => {
 
 /**
  * Check if `object` is a W3C `Blob` object (which `File` inherits from)
- *
- * @param  {*} obj
+ * @param {*} object - Object to check for
  * @return {boolean}
  */
 export const isBlob = object => {
@@ -45,32 +43,9 @@ export const isBlob = object => {
 	);
 };
 
-/**
- * Check if `obj` is a spec-compliant `FormData` object
- *
- * @param {*} object
- * @return {boolean}
- */
-export function isFormData(object) {
-	return (
-		typeof object === 'object' &&
-		typeof object.append === 'function' &&
-		typeof object.set === 'function' &&
-		typeof object.get === 'function' &&
-		typeof object.getAll === 'function' &&
-		typeof object.delete === 'function' &&
-		typeof object.keys === 'function' &&
-		typeof object.values === 'function' &&
-		typeof object.entries === 'function' &&
-		typeof object.constructor === 'function' &&
-		object[NAME] === 'FormData'
-	);
-}
-
 /**
  * Check if `obj` is an instance of AbortSignal.
- *
- * @param  {*} obj
+ * @param {*} object - Object to check for
  * @return {boolean}
  */
 export const isAbortSignal = object => {
@@ -81,4 +56,3 @@ export const isAbortSignal = object => {
 		)
 	);
 };
-