From 1b2983eaa9e3ec6487d0fcdc661424b312247656 Mon Sep 17 00:00:00 2001
From: Satyajit Sahoo <satyajit.happy@gmail.com>
Date: Fri, 30 Aug 2019 20:15:54 +0200
Subject: [PATCH] fix: handle route names change when all routes are removed
 (#86)

---
 packages/example/src/Screens/AuthFlow.tsx     | 128 ++++++++++++++++++
 packages/example/src/index.tsx                |   5 +
 .../routers/__tests__/StackRouter.test.tsx    |  62 ++++++++-
 packages/routers/src/StackRouter.tsx          |  16 ++-
 4 files changed, 208 insertions(+), 3 deletions(-)
 create mode 100644 packages/example/src/Screens/AuthFlow.tsx

diff --git a/packages/example/src/Screens/AuthFlow.tsx b/packages/example/src/Screens/AuthFlow.tsx
new file mode 100644
index 00000000..4cbd937b
--- /dev/null
+++ b/packages/example/src/Screens/AuthFlow.tsx
@@ -0,0 +1,128 @@
+import * as React from 'react';
+import { View, TextInput, ActivityIndicator, StyleSheet } from 'react-native';
+import { Title, Button } from 'react-native-paper';
+import { ParamListBase } from '@react-navigation/core';
+import {
+  createStackNavigator,
+  HeaderBackButton,
+  StackNavigationProp,
+} from '@react-navigation/stack';
+
+type AuthStackParams = {
+  splash: undefined;
+  home: undefined;
+  'sign-in': undefined;
+};
+
+const SplashScreen = () => (
+  <View style={styles.content}>
+    <ActivityIndicator />
+  </View>
+);
+
+const SignInScreen = ({
+  setUserToken,
+}: {
+  setUserToken: (token: string) => void;
+}) => {
+  return (
+    <View style={styles.content}>
+      <TextInput placeholder="Username" style={styles.input} />
+      <TextInput placeholder="Password" secureTextEntry style={styles.input} />
+      <Button
+        mode="contained"
+        onPress={() => setUserToken('token')}
+        style={styles.button}
+      >
+        Sign in
+      </Button>
+    </View>
+  );
+};
+
+const HomeScreen = ({
+  setUserToken,
+}: {
+  setUserToken: (token: undefined) => void;
+}) => {
+  return (
+    <View style={styles.content}>
+      <Title style={styles.text}>Signed in successfully 🎉</Title>
+      <Button onPress={() => setUserToken(undefined)} style={styles.button}>
+        Sign out
+      </Button>
+    </View>
+  );
+};
+
+const SimpleStack = createStackNavigator<AuthStackParams>();
+
+type Props = {
+  navigation: StackNavigationProp<ParamListBase>;
+};
+
+export default function SimpleStackScreen({ navigation }: Props) {
+  const [isLoading, setIsLoading] = React.useState(true);
+  const [userToken, setUserToken] = React.useState<string | undefined>(
+    undefined
+  );
+
+  React.useEffect(() => {
+    const timer = setTimeout(() => setIsLoading(false), 1000);
+
+    return () => clearTimeout(timer);
+  }, []);
+
+  navigation.setOptions({
+    header: null,
+  });
+
+  return (
+    <SimpleStack.Navigator
+      screenOptions={{
+        headerLeft: () => (
+          <HeaderBackButton onPress={() => navigation.goBack()} />
+        ),
+      }}
+    >
+      {isLoading ? (
+        <SimpleStack.Screen
+          name="splash"
+          component={SplashScreen}
+          options={{ title: `Auth Flow` }}
+        />
+      ) : userToken === undefined ? (
+        <SimpleStack.Screen name="sign-in" options={{ title: `Sign in` }}>
+          {() => <SignInScreen setUserToken={setUserToken} />}
+        </SimpleStack.Screen>
+      ) : (
+        <SimpleStack.Screen name="home" options={{ title: 'Home' }}>
+          {() => <HomeScreen setUserToken={setUserToken} />}
+        </SimpleStack.Screen>
+      )}
+    </SimpleStack.Navigator>
+  );
+}
+
+const styles = StyleSheet.create({
+  content: {
+    flex: 1,
+    padding: 16,
+    justifyContent: 'center',
+  },
+  input: {
+    margin: 8,
+    padding: 10,
+    backgroundColor: 'white',
+    borderRadius: 3,
+    borderWidth: StyleSheet.hairlineWidth,
+    borderColor: 'rgba(0, 0, 0, 0.08)',
+  },
+  button: {
+    margin: 8,
+  },
+  text: {
+    textAlign: 'center',
+    margin: 8,
+  },
+});
diff --git a/packages/example/src/index.tsx b/packages/example/src/index.tsx
index fcbf1481..cef92dc2 100644
--- a/packages/example/src/index.tsx
+++ b/packages/example/src/index.tsx
@@ -23,6 +23,7 @@ import SimpleStackScreen from './Screens/SimpleStack';
 import BottomTabsScreen from './Screens/BottomTabs';
 import MaterialTopTabsScreen from './Screens/MaterialTopTabs';
 import MaterialBottomTabs from './Screens/MaterialBottomTabs';
+import AuthFlow from './Screens/AuthFlow';
 
 YellowBox.ignoreWarnings(['Require cycle:', 'Warning: Async Storage']);
 
@@ -47,6 +48,10 @@ const SCREENS = {
     title: 'Material Bottom Tabs',
     component: MaterialBottomTabs,
   },
+  'auth-flow': {
+    title: 'Auth Flow',
+    component: AuthFlow,
+  },
 };
 
 const Drawer = createDrawerNavigator<RootDrawerParamList>();
diff --git a/packages/routers/__tests__/StackRouter.test.tsx b/packages/routers/__tests__/StackRouter.test.tsx
index a3adc610..de5210d3 100644
--- a/packages/routers/__tests__/StackRouter.test.tsx
+++ b/packages/routers/__tests__/StackRouter.test.tsx
@@ -138,7 +138,7 @@ it('gets state on route names change', () => {
   expect(
     router.getStateForRouteNamesChange(
       {
-        index: 0,
+        index: 2,
         key: 'stack-test',
         routeNames: ['bar', 'baz', 'qux'],
         routes: [
@@ -157,7 +157,7 @@ it('gets state on route names change', () => {
       }
     )
   ).toEqual({
-    index: 0,
+    index: 1,
     key: 'stack-test',
     routeNames: ['qux', 'baz', 'foo', 'fiz'],
     routes: [
@@ -166,6 +166,64 @@ it('gets state on route names change', () => {
     ],
     stale: false,
   });
+
+  expect(
+    router.getStateForRouteNamesChange(
+      {
+        index: 1,
+        key: 'stack-test',
+        routeNames: ['foo', 'bar'],
+        routes: [
+          { key: 'foo-test', name: 'foo' },
+          { key: 'bar-test', name: 'bar' },
+        ],
+        stale: false,
+      },
+      {
+        routeNames: ['baz', 'qux'],
+        routeParamList: {
+          baz: { name: 'John' },
+        },
+      }
+    )
+  ).toEqual({
+    index: 0,
+    key: 'stack-test',
+    routeNames: ['baz', 'qux'],
+    routes: [{ key: 'baz-test', name: 'baz', params: { name: 'John' } }],
+    stale: false,
+  });
+});
+
+it('gets state on route names change with initialRouteName', () => {
+  const router = StackRouter({ initialRouteName: 'qux' });
+
+  expect(
+    router.getStateForRouteNamesChange(
+      {
+        index: 1,
+        key: 'stack-test',
+        routeNames: ['foo', 'bar'],
+        routes: [
+          { key: 'foo-test', name: 'foo' },
+          { key: 'bar-test', name: 'bar' },
+        ],
+        stale: false,
+      },
+      {
+        routeNames: ['baz', 'qux'],
+        routeParamList: {
+          baz: { name: 'John' },
+        },
+      }
+    )
+  ).toEqual({
+    index: 0,
+    key: 'stack-test',
+    routeNames: ['baz', 'qux'],
+    routes: [{ key: 'qux-test', name: 'qux' }],
+    stale: false,
+  });
 });
 
 it('handles navigate action', () => {
diff --git a/packages/routers/src/StackRouter.tsx b/packages/routers/src/StackRouter.tsx
index 98629da0..21b20fea 100644
--- a/packages/routers/src/StackRouter.tsx
+++ b/packages/routers/src/StackRouter.tsx
@@ -114,11 +114,25 @@ export default function StackRouter(options: StackRouterOptions) {
       };
     },
 
-    getStateForRouteNamesChange(state, { routeNames }) {
+    getStateForRouteNamesChange(state, { routeNames, routeParamList }) {
       const routes = state.routes.filter(route =>
         routeNames.includes(route.name)
       );
 
+      if (routes.length === 0) {
+        const initialRouteName =
+          options.initialRouteName !== undefined &&
+          routeNames.includes(options.initialRouteName)
+            ? options.initialRouteName
+            : routeNames[0];
+
+        routes.push({
+          key: `${initialRouteName}-${shortid()}`,
+          name: initialRouteName,
+          params: routeParamList[initialRouteName],
+        });
+      }
+
       return {
         ...state,
         routeNames,