(chore) - support __source for jsx-sourcemaps (preactjs#1628)

* chore: support __source for jsx-sourcemaps

* refactor: pr remark

Author: JoviDeCroock

debug/src/debug.js

@@ -140,6 +140,12 @@ export function initDebug() {
 	};
 
 	options.vnode = (vnode) => {
+		let source;
+		if (vnode.props && vnode.props.__source) {
+			source = vnode.props.__source;
+			delete vnode.props.__source;
+		}
+		vnode.__source = source;
 		Object.defineProperties(vnode, deprecatedAttributes);
 		if (oldVnode) oldVnode(vnode);
 	};

debug/test/browser/debug.test.js

@@ -82,6 +82,20 @@ describe('debug', () => {
 		expect(fn).to.throw(/createElement/);
 	});
 
+	it('should add __source to the vnode in debug mode.', () => {
+		const vnode = h('div', {
+			__source: {
+				fileName: 'div.jsx',
+				lineNumber: 3
+			}
+		});
+		expect(vnode.__source).to.deep.equal({
+			fileName: 'div.jsx',
+			lineNumber: 3
+		});
+		expect(vnode.props.__source).to.be.undefined;
+	});
+
 	it('should throw an error when using a hook outside a render', () => {
 		class App extends Component {
 			componentWillMount() {