From 054167f67303c1b3cdb18710d477211811c4e760 Mon Sep 17 00:00:00 2001
From: Alex Brazier <aejbrazier.apps@gmail.com>
Date: Sun, 13 Sep 2020 22:50:35 +0100
Subject: [PATCH] feat: Add option to use existing back button to navigate
 (#24)

* feat: Add option to use existing back button to navigate

- Add an option that allows you to set your own back button, e.g. in the nav header and use that to navigate around the network logger
- Handle hardware back press when on details page

* Remove padding when close button is hidden
---
 README.md                         | 22 +++++++++++++++-
 example/src/App.tsx               | 42 ++++++++++++++++++++++++++++---
 src/backHandler.ts                | 41 ++++++++++++++++++++++++++++++
 src/components/NetworkLogger.tsx  | 36 +++++++++++++++++++++++---
 src/components/RequestDetails.tsx |  9 ++++---
 src/components/ResultItem.tsx     |  3 ++-
 src/index.tsx                     |  2 ++
 7 files changed, 143 insertions(+), 12 deletions(-)
 create mode 100644 src/backHandler.ts

diff --git a/README.md b/README.md
index 7a142ed..34346d9 100644
--- a/README.md
+++ b/README.md
@@ -91,20 +91,40 @@ const MyScreen = () => <NetworkLogger theme="dark" />;
 
 ### Logging options
 
+#### Max Requests
+
 You can configure the max number of requests stored on the device using by calling `startNetworkLogging` with the `maxRequests` option. The default is `500`.
 
 ```ts
 startNetworkLogging({ maxRequests: 500 });
 ```
 
+#### Sorting
+
 Set the sort order of requests. Options are `asc` or `desc`, default is `desc` (most recent at the top).
 
-```ts
+```tsx
 import NetworkLogger from 'react-native-network-logger';
 
 const MyScreen = () => <NetworkLogger sort="asc" />;
 ```
 
+#### Integrate with existing navigation
+
+Use your existing back button (e.g. in your navigation header) to navigate within the network logger.
+
+```tsx
+import NetworkLogger, { getBackHandler } from 'react-native-network-logger';
+
+const onBack = getBackHandler(navigate.onBack);
+
+const MyScreen = () => (
+  <Screen onBackPressed={onBack}>
+    <NetworkLogger />
+  </Screen>
+);
+```
+
 ## Example App
 
 To test the example app, after cloning the repo, install the required dependencies by running:
diff --git a/example/src/App.tsx b/example/src/App.tsx
index 0459ff0..0fb20ce 100644
--- a/example/src/App.tsx
+++ b/example/src/App.tsx
@@ -6,8 +6,13 @@ import {
   Platform,
   View,
   Text,
+  Alert,
+  TouchableOpacity,
 } from 'react-native';
-import NetworkLogger, { ThemeName } from 'react-native-network-logger';
+import NetworkLogger, {
+  ThemeName,
+  getBackHandler,
+} from 'react-native-network-logger';
 
 export default function App() {
   const formData = new FormData();
@@ -36,11 +41,27 @@ export default function App() {
 
   const styles = themedStyles(theme === 'dark');
 
+  const goBack = () => {
+    Alert.alert('Going back');
+  };
+
+  const backHandler = getBackHandler(goBack);
+
   return (
     <SafeAreaView style={styles.container}>
-      <Text style={styles.title} accessibilityRole="header">
-        react-native-network-logger
-      </Text>
+      <View style={styles.header}>
+        <TouchableOpacity
+          style={styles.navButton}
+          onPress={backHandler}
+          hitSlop={{ top: 20, left: 20, bottom: 20, right: 20 }}
+        >
+          <Text style={styles.backButtonText}>{'‹'}</Text>
+        </TouchableOpacity>
+        <Text style={styles.title} accessibilityRole="header">
+          react-native-network-logger
+        </Text>
+        <View style={styles.navButton} />
+      </View>
       <NetworkLogger theme={theme} />
       <View style={styles.bottomView}>
         <Button
@@ -60,7 +81,20 @@ const themedStyles = (dark = false) =>
       backgroundColor: dark ? '#2d2a28' : 'white',
       paddingTop: Platform.OS === 'android' ? 25 : 0,
     },
+    header: {
+      flexDirection: 'row',
+    },
+    navButton: {
+      flex: 1,
+    },
+    backButtonText: {
+      color: dark ? 'white' : 'black',
+      paddingHorizontal: 20,
+      fontSize: 30,
+      fontWeight: 'bold',
+    },
     title: {
+      flex: 5,
       color: dark ? 'white' : 'black',
       textAlign: 'center',
       padding: 10,
diff --git a/src/backHandler.ts b/src/backHandler.ts
new file mode 100644
index 0000000..ed76d4a
--- /dev/null
+++ b/src/backHandler.ts
@@ -0,0 +1,41 @@
+let appBackHandler: (() => any) | undefined;
+let networkLoggerBackHandler: (() => void) | undefined;
+
+export const setBackHandler = (backHandler?: () => void) => {
+  networkLoggerBackHandler = backHandler;
+};
+
+const goBack = () => {
+  if (networkLoggerBackHandler) {
+    return networkLoggerBackHandler();
+  }
+  appBackHandler?.();
+};
+
+export const backHandlerSet = () => {
+  return !!appBackHandler;
+};
+
+/**
+ * Get a replacement back handler to use instead of your default navigation so you
+ * can use your existing back button to navigate inside the network logger.
+ *
+ * If navigation has occurred in the logger app then pressing your back handler will
+ * navigate internally. If it is already on the default page then it will call your
+ * original back handler.
+ *
+ * e.g.
+ *
+ * const navigation = useNavigation()
+ *
+ * const onBack = getBackHandler(navigation.goBack)
+ *
+ * <Button onPress={onBack} title="Go back" />
+ *
+ * @param backHandler App navigation default back handler
+ */
+export const getBackHandler = (backHandler: () => any) => {
+  appBackHandler = backHandler;
+
+  return goBack;
+};
diff --git a/src/components/NetworkLogger.tsx b/src/components/NetworkLogger.tsx
index 593949f..c32371b 100644
--- a/src/components/NetworkLogger.tsx
+++ b/src/components/NetworkLogger.tsx
@@ -1,10 +1,11 @@
-import React, { useEffect, useState } from 'react';
-import { Alert, View, StyleSheet } from 'react-native';
+import React, { useEffect, useState, useCallback } from 'react';
+import { Alert, View, StyleSheet, BackHandler } from 'react-native';
 import logger from '../loggerSingleton';
 import NetworkRequestInfo from '../NetworkRequestInfo';
 import { ThemeContext, ThemeName } from '../theme';
 import RequestList from './RequestList';
 import RequestDetails from './RequestDetails';
+import { setBackHandler } from '../backHandler';
 
 interface Props {
   theme?: ThemeName;
@@ -23,7 +24,17 @@ const NetworkLogger: React.FC<Props> = ({ theme = 'light', sort = 'desc' }) => {
     sortRequests(logger.getRequests(), sort)
   );
   const [request, setRequest] = useState<NetworkRequestInfo>();
-  const [showDetails, setShowDetails] = useState(false);
+  const [showDetails, _setShowDetails] = useState(false);
+
+  const setShowDetails = useCallback((shouldShow: boolean) => {
+    _setShowDetails(shouldShow);
+
+    if (shouldShow) {
+      setBackHandler(() => setShowDetails(false));
+    } else {
+      setBackHandler(undefined);
+    }
+  }, []);
 
   useEffect(() => {
     logger.setCallback((updatedRequests: NetworkRequestInfo[]) => {
@@ -33,6 +44,25 @@ const NetworkLogger: React.FC<Props> = ({ theme = 'light', sort = 'desc' }) => {
     logger.enableXHRInterception();
   }, [sort]);
 
+  useEffect(() => {
+    const onBack = () => {
+      if (showDetails) {
+        setShowDetails(false);
+        return true;
+      }
+
+      // Let default back handler take over
+      return false;
+    };
+
+    const backHandler = BackHandler.addEventListener(
+      'hardwareBackPress',
+      onBack
+    );
+
+    return () => backHandler.remove();
+  }, [showDetails, setShowDetails]);
+
   const showMore = () => {
     Alert.alert('More Options', undefined, [
       {
diff --git a/src/components/RequestDetails.tsx b/src/components/RequestDetails.tsx
index ed6ce51..6535b1b 100644
--- a/src/components/RequestDetails.tsx
+++ b/src/components/RequestDetails.tsx
@@ -10,6 +10,7 @@ import {
 } from 'react-native';
 import NetworkRequestInfo from '../NetworkRequestInfo';
 import { useThemedStyles, Theme } from '../theme';
+import { backHandlerSet } from '../backHandler';
 import ResultItem from './ResultItem';
 import Header from './Header';
 import Button from './Button';
@@ -129,9 +130,11 @@ const RequestDetails: React.FC<Props> = ({ request, onClose }) => {
           Share as cURL
         </Button>
       </ScrollView>
-      <Button onPress={onClose} style={styles.close}>
-        Close
-      </Button>
+      {!backHandlerSet() && (
+        <Button onPress={onClose} style={styles.close}>
+          Close
+        </Button>
+      )}
     </View>
   );
 };
diff --git a/src/components/ResultItem.tsx b/src/components/ResultItem.tsx
index fb4692d..3276f29 100644
--- a/src/components/ResultItem.tsx
+++ b/src/components/ResultItem.tsx
@@ -2,6 +2,7 @@ import React from 'react';
 import { View, TouchableOpacity, Text, StyleSheet } from 'react-native';
 import NetworkRequestInfo from '../NetworkRequestInfo';
 import { Theme, useThemedStyles, useTheme } from '../theme';
+import { backHandlerSet } from '../backHandler';
 
 interface Props {
   request: NetworkRequestInfo;
@@ -79,7 +80,7 @@ const ResultItem: React.FC<Props> = ({ style, request, onPress }) => {
           styles.text,
           styles.content,
           getUrlTextColor(request.status),
-          onDetailsPage && styles.paddedUrl,
+          onDetailsPage && !backHandlerSet() && styles.paddedUrl,
         ]}
       >
         {request.url}
diff --git a/src/index.tsx b/src/index.tsx
index 385dd16..cbfab8d 100644
--- a/src/index.tsx
+++ b/src/index.tsx
@@ -11,4 +11,6 @@ export const getRequests = () => logger.getRequests();
 
 export const clearRequests = () => logger.clearRequests();
 
+export { getBackHandler } from './backHandler';
+
 export { ThemeName } from './theme';