Fix Portals not being unmounted

compat/src/index.js

@@ -73,6 +73,9 @@ class ContextProvider {
 function Portal(props) {
 	let wrap = h(ContextProvider, { context: this.context }, props.vnode);
 	render(wrap, props.container);
+	this.componentWillUnmount = () => {
+		render(null, props.container);
+	};
 	return null;
 }
 

compat/test/browser/portals.test.js

@@ -51,4 +51,30 @@ describe('Portal', () => {
 		render(<App />, root);
 		expect(scratch.firstChild.firstChild.childNodes.length).to.equal(0);
 	});
+
+	it('should unmount Portal', () => {
+		let root = document.createElement('div');
+		let dialog = document.createElement('div');
+		dialog.id = 'container';
+
+		scratch.appendChild(root);
+		scratch.appendChild(dialog);
+
+		function Dialog() {
+			return <div>Dialog content</div>;
+		}
+
+		function App() {
+			return (
+				<div>
+					{createPortal(<Dialog />, dialog)}
+				</div>
+			);
+		}
+
+		render(<App />, root);
+		expect(dialog.childNodes.length).to.equal(1);
+		render(null, root);
+		expect(dialog.childNodes.length).to.equal(0);
+	});
 });