feat: handle route names change

example/StackNavigator.tsx

@@ -88,6 +88,14 @@ const StackRouter: Router<CommonAction | Action> = {
     return state;
   },
 
+  getStateForRouteNamesChange(state, { routeNames }) {
+    return {
+      ...state,
+      routeNames,
+      routes: state.routes.filter(route => routeNames.includes(route.name)),
+    };
+  },
+
   getStateForAction(state, action) {
     switch (action.type) {
       case 'PUSH':

example/TabNavigator.tsx

@@ -72,6 +72,21 @@ const TabRouter: Router<Action | CommonAction> = {
     return state;
   },
 
+  getStateForRouteNamesChange(state, { routeNames, initialParamsList }) {
+    return {
+      ...state,
+      routeNames,
+      routes: routeNames.map(
+        name =>
+          state.routes.find(r => r.name === name) || {
+            name,
+            key: `${name}-${shortid()}`,
+            params: initialParamsList[name],
+          }
+      ),
+    };
+  },
+
   getStateForAction(state, action) {
     switch (action.type) {
       case 'JUMP_TO':
@@ -190,4 +205,4 @@ export function TabNavigator(props: Props) {
   );
 }
 
-export default createNavigator(TabNavigator);
+export default createNavigator(TabNavigator);

src/__tests__/index.test.tsx

@@ -41,6 +41,14 @@ export const MockRouter: Router<{ type: string }> & { key: number } = {
     return state;
   },
 
+  getStateForRouteNamesChange(state, { routeNames }) {
+    return {
+      ...state,
+      routeNames,
+      routes: state.routes.filter(route => routeNames.includes(route.name)),
+    };
+  },
+
   getStateForAction(state, action) {
     switch (action.type) {
       case 'UPDATE':
@@ -535,6 +543,41 @@ it('updates route params with setParams', () => {
   });
 });
 
+it('handles change in route names', () => {
+  const TestNavigator = (props: any): any => {
+    useNavigationBuilder(MockRouter, props);
+    return null;
+  };
+
+  const onStateChange = jest.fn();
+
+  const root = render(
+    <NavigationContainer onStateChange={onStateChange}>
+      <TestNavigator initialRouteName="bar">
+        <Screen name="foo" component={jest.fn()} />
+        <Screen name="bar" component={jest.fn()} />
+      </TestNavigator>
+    </NavigationContainer>
+  );
+
+  root.update(
+    <NavigationContainer onStateChange={onStateChange}>
+      <TestNavigator>
+        <Screen name="foo" component={jest.fn()} />
+        <Screen name="baz" component={jest.fn()} />
+        <Screen name="qux" component={jest.fn()} />
+      </TestNavigator>
+    </NavigationContainer>
+  );
+
+  expect(onStateChange).toBeCalledWith({
+    index: 1,
+    key: '0',
+    routeNames: ['foo', 'baz', 'qux'],
+    routes: [{ key: 'foo', name: 'foo' }],
+  });
+});
+
 it('throws if navigator is not inside a container', () => {
   const TestNavigator = (props: any) => {
     useNavigationBuilder(MockRouter, props);

src/types.tsx

@@ -54,9 +54,9 @@ export type Router<Action extends NavigationAction = CommonAction> = {
   /**
    * Initialize the navigation state.
    *
-   * @param routeNames List of valid route names as defined in the screen components.
-   * @param initialRouteName Route to focus in the state.
-   * @param initialParamsList Object containing initial params for each route.
+   * @param options.routeNames List of valid route names as defined in the screen components.
+   * @param options.initialRouteName Route to focus in the state.
+   * @param options.initialParamsList Object containing initial params for each route.
    */
   getInitialState(options: {
     routeNames: string[];
@@ -67,14 +67,31 @@ export type Router<Action extends NavigationAction = CommonAction> = {
   /**
    * Rehydrate the full navigation state from a given partial state.
    *
-   * @param routeNames List of valid route names as defined in the screen components.
-   * @param partialState Navigation state to rehydrate from.
+   * @param options.routeNames List of valid route names as defined in the screen components.
+   * @param options.partialState Navigation state to rehydrate from.
    */
   getRehydratedState(options: {
     routeNames: string[];
     partialState: NavigationState | PartialState;
   }): NavigationState;
 
+  /**
+   * Take the current state and updated list of route names, and return a new state.
+   *
+   * @param state State object to update.
+   * @param options.routeNames New list of route names.
+   * @param options.initialRouteName Route to focus in the state.
+   * @param options.initialParamsList Object containing initial params for each route.
+   */
+  getStateForRouteNamesChange(
+    state: NavigationState,
+    options: {
+      routeNames: string[];
+      initialRouteName: string;
+      initialParamsList: ParamListBase;
+    }
+  ): NavigationState;
+
   /**
    * Take the current state and action, and return a new state.
    * If the action cannot be handled, return `null`.

src/useNavigationBuilder.tsx

@@ -14,6 +14,9 @@ type Options = {
   children: React.ReactNode;
 };
 
+const isArrayEqual = (a: any[], b: any[]) =>
+  a.length === b.length && a.every((it, index) => it === b[index]);
+
 export default function useNavigationBuilder(
   router: Router<any>,
   options: Options
@@ -78,6 +81,24 @@ export default function useNavigationBuilder(
     partialState: currentState,
   });
 
+  if (!isArrayEqual(state.routeNames, routeNames)) {
+    // When the list of route names change, the router should handle it to remove invalid routes
+    const nextState = router.getStateForRouteNamesChange(state, {
+      routeNames,
+      initialRouteName,
+      initialParamsList,
+    });
+
+    if (state !== nextState) {
+      // If the state needs to be updated, we'll schedule an update with React
+      // setState in render seems hacky, but that's how React docs implement getDerivedPropsFromState
+      // https://reactjs.org/docs/hooks-faq.html#how-do-i-implement-getderivedstatefromprops
+      setState(nextState);
+    }
+
+    state = nextState;
+  }
+
   React.useEffect(() => {
     return () => {
       // We need to clean up state for this navigator on unmount