Merge pull request #2 from zeh/keep-previous-handler

Keep previous handler

Author: a7ul

README.md

@@ -1,7 +1,7 @@
 # react-native-exception-handler
 
 A react native module that lets you to register a global error handler that can capture fatal/non fatal uncaught exceptions.
-The module helps prevent abrupt crashing of RN Apps without a graceful message to the user.   
+The module helps prevent abrupt crashing of RN Apps without a graceful message to the user.
 
 In the current scenario:
   - `In DEV mode , you get a RED Screen error pointing your JS errors.`
@@ -46,9 +46,14 @@ setJSExceptionHandler(errorHandler); // registering the error handler (maybe u c
 or
 
 setJSExceptionHandler(errorHandler, true); //Second argument true is basically
-                                        //if u need the handler to be called in place of RED  
+                                        //if u need the handler to be called in place of RED
                                         //screen in development mode also
-```                                     
+or
+
+setJSExceptionHandler(errorHandler, true, true); //Third argument allows adding it
+                                              //as a new handler, but keeping the previous one
+                                              //(it will run errorHandler but still show the red screen)
+```
 
 
 ### Screens

examples/bugCaptureOnError.js

@@ -1,5 +1,4 @@
 import {Alert} from 'react-native';
-import {BackAndroid} from 'react-native';
 import {setJSExceptionHandler} from 'react-native-exception-handler';
 
 const reporter = (error) => {

examples/seamlessCapture.js

@@ -0,0 +1,18 @@
+import {setJSExceptionHandler} from 'react-native-exception-handler';
+
+const reporter = (error) => {
+  // Logic for reporting to devs
+  // Example : Log issues to github issues using github apis.
+  console.log(error); // sample
+};
+
+const errorHandler = (e, isFatal) => {
+  if (isFatal) {
+    reporter(e);
+  } else {
+    console.log(e); // So that we can see it in the ADB logs in case of Android if needed
+  }
+};
+
+// We will still see the error screen, but our reporter() function will be called
+setJSExceptionHandler(errorHandler, false, true);

index.js

@@ -1,9 +1,17 @@
 const noop = () => {};
 
-export const setJSExceptionHandler = (customHandler = noop, allowedInDevMode = false) => {
+export const setJSExceptionHandler = (customHandler = noop, allowedInDevMode = false, keepPreviousHandler = false) => {
   const allowed = allowedInDevMode ? true : !__DEV__;
   if (allowed) {
-    global.ErrorUtils.setGlobalHandler(customHandler);
+    if (keepPreviousHandler) {
+      const previousHandler = global.ErrorUtils.getGlobalHandler();
+      global.ErrorUtils.setGlobalHandler((error, isFatal) => {
+        customHandler(error, isFatal);
+        previousHandler(error, isFatal);
+      });
+    } else {
+      global.ErrorUtils.setGlobalHandler(customHandler);
+    }
   } else {
     console.log('Skipping setJSExceptionHandler: Reason: In DEV mode and allowedInDevMode = false');
   }