Allow pure-wildcard route for nested navigators. (#2929)

* Allow pure-wildcard route for nested navigators.

* Treat empty paths as they are.

packages/react-navigation/src/routers/StackRouter.js

@@ -46,24 +46,42 @@ export default (routeConfigs, stackConfig = {}) => {
   const initialRouteName = stackConfig.initialRouteName || routeNames[0];
 
   const initialChildRouter = childRouters[initialRouteName];
-  const paths = stackConfig.paths || {};
+  const pathsByRouteNames = { ...stackConfig.paths } || {};
+  let paths = [];
 
   // Build paths for each route
   routeNames.forEach(routeName => {
-    let pathPattern = paths[routeName] || routeConfigs[routeName].path;
-    const matchExact = !!pathPattern && !childRouters[routeName];
-    if (typeof pathPattern !== 'string') {
+    let pathPattern =
+      pathsByRouteNames[routeName] || routeConfigs[routeName].path;
+    let matchExact = !!pathPattern && !childRouters[routeName];
+    if (pathPattern === undefined) {
       pathPattern = routeName;
     }
     const keys = [];
-    let re = pathToRegexp(pathPattern, keys);
+    let re, toPath, priority;
+    if (typeof pathPattern === 'string') {
+      // pathPattern may be either a string or a regexp object according to path-to-regexp docs.
+      re = pathToRegexp(pathPattern, keys);
+      toPath = pathToRegexp.compile(pathPattern);
+      priority = 0;
+    } else {
+      // for wildcard match
+      re = pathToRegexp('*', keys);
+      toPath = () => '';
+      matchExact = true;
+      priority = -1;
+    }
     if (!matchExact) {
       const wildcardRe = pathToRegexp(`${pathPattern}/*`, keys);
       re = new RegExp(`(?:${re.source})|(?:${wildcardRe.source})`);
     }
-    paths[routeName] = { re, keys, toPath: pathToRegexp.compile(pathPattern) };
+    pathsByRouteNames[routeName] = { re, keys, toPath, priority };
   });
 
+  paths = Object.entries(pathsByRouteNames);
+  /* $FlowFixMe */
+  paths.sort((a: [string, *], b: [string, *]) => b[1].priority - a[1].priority);
+
   return {
     getComponentForState(state) {
       const activeChildRoute = state.routes[state.index];
@@ -293,7 +311,7 @@ export default (routeConfigs, stackConfig = {}) => {
       const route = state.routes[state.index];
       const routeName = route.routeName;
       const screen = getScreenForRouteName(routeConfigs, routeName);
-      const subPath = paths[routeName].toPath(route.params);
+      const subPath = pathsByRouteNames[routeName].toPath(route.params);
       let path = subPath;
       let params = route.params;
       if (screen && screen.router) {
@@ -328,7 +346,7 @@ export default (routeConfigs, stackConfig = {}) => {
       let pathMatchKeys;
 
       // eslint-disable-next-line no-restricted-syntax
-      for (const [routeName, path] of Object.entries(paths)) {
+      for (const [routeName, path] of paths) {
         const { re, keys } = path;
         pathMatch = re.exec(pathNameToResolve);
         if (pathMatch && pathMatch.length) {
@@ -340,6 +358,13 @@ export default (routeConfigs, stackConfig = {}) => {
 
       // We didn't match -- return null
       if (!matchedRouteName) {
+        // If the path is empty (null or empty string)
+        // just return the initial route action
+        if (!pathToResolve) {
+          return NavigationActions.navigate({
+            routeName: initialRouteName,
+          });
+        }
         return null;
       }
 
@@ -353,6 +378,9 @@ export default (routeConfigs, stackConfig = {}) => {
         nestedAction = childRouters[matchedRouteName].getActionForPathAndParams(
           pathMatch.slice(pathMatchKeys.length).join('/') + nestedQueryString
         );
+        if (!nestedAction) {
+          return null;
+        }
       }
 
       // reduce the items of the query string. any query params may

packages/react-navigation/src/routers/__tests__/StackRouter-test.js

@@ -54,6 +54,10 @@ const TestStackRouter = StackRouter({
   main: {
     screen: MainNavigator,
   },
+  baz: {
+    path: null,
+    screen: FooNavigator,
+  },
   auth: {
     screen: AuthNavigator,
   },
@@ -277,6 +281,22 @@ describe('StackRouter', () => {
     });
   });
 
+  test('Correctly parses a path to the router connected to another router through a pure wildcard route into an action chain', () => {
+    const uri = 'b/123';
+    const action = TestStackRouter.getActionForPathAndParams(uri);
+    expect(action).toEqual({
+      type: NavigationActions.NAVIGATE,
+      routeName: 'baz',
+      action: {
+        type: NavigationActions.NAVIGATE,
+        routeName: 'bar',
+        params: {
+          barThing: '123',
+        },
+      },
+    });
+  });
+
   test('Correctly returns null action for non-existent path', () => {
     const uri = 'asdf/1234';
     const action = TestStackRouter.getActionForPathAndParams(uri);
@@ -944,6 +964,89 @@ describe('StackRouter', () => {
     expect(params.bazId).toEqual('321');
   });
 
+  test('Gets deep path with pure wildcard match', () => {
+    const ScreenA = () => <div />;
+    const ScreenB = () => <div />;
+    const ScreenC = () => <div />;
+    ScreenA.router = StackRouter({
+      Boo: { path: 'boo', screen: ScreenC },
+      Baz: { path: 'baz/:bazId', screen: ScreenB },
+    });
+    ScreenC.router = StackRouter({
+      Boo2: { path: '', screen: ScreenB },
+    });
+    const router = StackRouter({
+      Foo: {
+        path: null,
+        screen: ScreenA,
+      },
+      Bar: {
+        screen: ScreenB,
+      },
+    });
+
+    {
+      const state = {
+        index: 0,
+        routes: [
+          {
+            index: 1,
+            key: 'Foo',
+            routeName: 'Foo',
+            params: {
+              id: '123',
+            },
+            routes: [
+              {
+                index: 0,
+                key: 'Boo',
+                routeName: 'Boo',
+                routes: [{ key: 'Boo2', routeName: 'Boo2' }],
+              },
+              { key: 'Baz', routeName: 'Baz', params: { bazId: '321' } },
+            ],
+          },
+          { key: 'Bar', routeName: 'Bar' },
+        ],
+      };
+      const { path, params } = router.getPathAndParamsForState(state);
+      expect(path).toEqual('baz/321');
+      /* $FlowFixMe: params.id has to exist */
+      expect(params.id).toEqual('123');
+      /* $FlowFixMe: params.bazId has to exist */
+      expect(params.bazId).toEqual('321');
+    }
+
+    {
+      const state = {
+        index: 0,
+        routes: [
+          {
+            index: 0,
+            key: 'Foo',
+            routeName: 'Foo',
+            params: {
+              id: '123',
+            },
+            routes: [
+              {
+                index: 0,
+                key: 'Boo',
+                routeName: 'Boo',
+                routes: [{ key: 'Boo2', routeName: 'Boo2' }],
+              },
+              { key: 'Baz', routeName: 'Baz', params: { bazId: '321' } },
+            ],
+          },
+          { key: 'Bar', routeName: 'Bar' },
+        ],
+      };
+      const { path, params } = router.getPathAndParamsForState(state);
+      expect(path).toEqual('boo/');
+      expect(params).toEqual({ id: '123' });
+    }
+  });
+
   test('Maps old actions (uses "Handles the reset action" test)', () => {
     global.console.warn = jest.fn();
     const router = StackRouter({