fix(router): handle empty path with query params

modules/@angular/router/src/url_tree.ts

@@ -277,7 +277,11 @@ class UrlParser {
   }
 
   parseRootSegment(): UrlSegment {
-    if (this.remaining === '' || this.remaining === '/') {
+    if (this.remaining.startsWith('/')) {
+      this.capture('/');
+    }
+
+    if (this.remaining === '' || this.remaining.startsWith('?')) {
       return new UrlSegment([], {});
     } else {
       return new UrlSegment([], this.parseSegmentChildren());

modules/@angular/router/test/url_serializer.spec.ts

@@ -91,6 +91,13 @@ describe('url serializer', () => {
     expect(url.serialize(tree)).toEqual('/one;a=true');
   });
 
+  it('should parse query params (root)', () => {
+    const tree = url.parse('/?a=1&b=2');
+    expect(tree.root.children).toEqual({});
+    expect(tree.queryParams).toEqual({a: '1', b: '2'});
+    expect(url.serialize(tree)).toEqual('/?a=1&b=2');
+  });
+
   it('should parse query params', () => {
     const tree = url.parse('/one?a=1&b=2');
     expect(tree.queryParams).toEqual({a: '1', b: '2'});