Disable onChange and route() during SSR

src/index.js

@@ -151,7 +151,7 @@ class Router extends Component {
 		this.state = {
 			url: props.url || getCurrentUrl()
 		};
-
+		
 		initEventListeners();
 	}
 
@@ -179,7 +179,12 @@ class Router extends Component {
 	}
 
 	componentWillMount() {
-		ROUTERS.push(this);
+		// preact-render-to-string does not initialize the "next state" field for components.
+		// We can use this to detect a static rendering environment and disable subscriptions.
+		this._ssr = !('_nextState' in this || '__s' in this);
+		if (!this._ssr) {
+			ROUTERS.push(this);
+		}
 		this.updating = true;
 	}
 
@@ -194,7 +199,7 @@ class Router extends Component {
 
 	componentWillUnmount() {
 		if (typeof this.unlisten==='function') this.unlisten();
-		ROUTERS.splice(ROUTERS.indexOf(this), 1);
+		ROUTERS.splice(ROUTERS.indexOf(this) >>> 0, 1);
 	}
 
 	componentWillUpdate() {
@@ -230,7 +235,7 @@ class Router extends Component {
 		let current = active[0] || null;
 
 		let previous = this.previousUrl;
-		if (url!==previous) {
+		if (!this._ssr && url!==previous) {
 			this.previousUrl = url;
 			if (typeof onChange==='function') {
 				onChange({

test/index.js

@@ -4,6 +4,14 @@ import assertCloneOf from '../test_helpers/assert-clone-of';
 
 chai.use(assertCloneOf);
 
+function createBrowserRouter(props) {
+	const router = new Router(props);
+	router.__s = router.state || {};  // _nextState
+	router.__d = true;  // _dirty
+	router.componentWillMount();
+	return router;
+}
+
 describe('preact-router', () => {
 	it('should export Router, Link and route', () => {
 		expect(Router).to.be.a('function');
@@ -13,7 +21,7 @@ describe('preact-router', () => {
 
 	describe('Router', () => {
 		it('should filter children based on URL', () => {
-			let router = new Router({});
+			let router = createBrowserRouter({});
 			let children = [
 				<foo path="/" />,
 				<foo path="/foo" />,
@@ -34,7 +42,7 @@ describe('preact-router', () => {
 		});
 
 		it('should support nested parameterized routes', () => {
-			let router = new Router({});
+			let router = createBrowserRouter({});
 			let children = [
 				<foo path="/foo" />,
 				<foo path="/foo/:bar" />,
@@ -55,7 +63,7 @@ describe('preact-router', () => {
 		});
 
 		it('should support default routes', () => {
-			let router = new Router({});
+			let router = createBrowserRouter({});
 			let children = [
 				<foo default />,
 				<foo path="/" />,
@@ -76,7 +84,7 @@ describe('preact-router', () => {
 		});
 
 		it('should support initial route prop', () => {
-			let router = new Router({ url:'/foo' });
+			let router = createBrowserRouter({ url:'/foo' });
 			let children = [
 				<foo default />,
 				<foo path="/" />,
@@ -87,14 +95,14 @@ describe('preact-router', () => {
 				router.render({ children }, router.state)
 			).to.be.cloneOf(children[2]);
 
-			expect(new Router({})).to.have.deep.property('state.url', location.pathname + (location.search || ''));
+			expect(createBrowserRouter({})).to.have.deep.property('state.url', location.pathname + (location.search || ''));
 		});
 
 		it('should support custom history', () => {
 			let push = sinon.spy();
 			let replace = sinon.spy();
 			let getCurrentLocation = sinon.spy(() => ({pathname: '/initial'}));
-			let router = new Router({
+			let router = createBrowserRouter({
 				history: { push, replace, getCurrentLocation },
 				children: [
 					<index path="/" />,
@@ -123,7 +131,7 @@ describe('preact-router', () => {
 		let router;
 
 		before( () => {
-			router = new Router({
+			router = createBrowserRouter({
 				url: '/foo',
 				children: [
 					<foo path="/" />,