AbortController ponyfill

package.json

@@ -11,7 +11,8 @@
     "test": "eslint src test && jest",
     "build": "microbundle src/index.mjs && microbundle -f cjs polyfill/polyfill.mjs -o polyfill/index.js --no-sourcemap && cp dist/unfetch.mjs dist/unfetch.es.js",
     "prepare": "npm run -s build",
-    "release": "cross-var npm run build -s && cross-var git commit -am $npm_package_version && cross-var git tag $npm_package_version && git push && git push --tags && npm publish"
+    "release": "cross-var npm run build -s && cross-var git commit -am $npm_package_version && cross-var git tag $npm_package_version && git push && git push --tags && npm publish",
+    "format": "eslint {src,test}  --fix"
   },
   "repository": "developit/unfetch",
   "keywords": [

src/AbortController.mjs

@@ -0,0 +1,6 @@
+export default function() {
+	this.signal = { onabort: () => {} };
+	this.abort = () => {
+		this.signal.onabort();
+	};
+}

src/index.mjs

@@ -17,6 +17,9 @@ export default function(url, options) {
 
 		request.onerror = reject;
 
+		if (options.signal) options.signal.onabort = () => { request.abort(); }
+		request.onabort = () => reject(new DOMException('The user aborted a request.'));
+
 		request.send(options.body || null);
 
 		function response() {

test/AbortController.js

@@ -0,0 +1,46 @@
+import fetch from '../src/index.mjs';
+import AbortController from '../src/AbortController.mjs';
+
+describe('AbortController', () => {
+	it('should be a function', () => {
+		expect(AbortController).toEqual(expect.any(Function));
+	});
+
+	describe('AbortController()', () => {
+		let xhr;
+
+		beforeEach(() => {
+			xhr = {
+				setRequestHeader: jest.fn(),
+				getAllResponseHeaders: jest.fn().mockReturnValue('X-Foo: bar\nX-Foo:baz'),
+				open: jest.fn(),
+				send: jest.fn(),
+				abort: jest.fn(() => xhr.onabort({ type: 'abort' })) ,
+				status: 200,
+				statusText: 'OK',
+				responseText: '{"a":"b"}',
+				responseURL: '/foo?redirect'
+			};
+
+			global.XMLHttpRequest = jest.fn(() => xhr);
+		});
+
+		afterEach(() => {
+			delete global.XMLHttpRequest;
+		});
+
+		it('handles abort', () => {
+			let controller = new AbortController();
+			let signal = controller.signal;
+			let p = fetch('/foo', { signal })
+				.then(() => {})
+				.catch((e) => {
+					expect(e.message).toEqual('The user aborted a request.');
+				});
+
+			controller.abort();
+
+			return p;
+		});
+	});
+});