[JS] JS API for global handling of unhandled exceptions

The API I envision is similar to window.onerror but not necessarily the same. This would allow us to make RCTExceptionsManager.reportUnhandledException a lot smaller (we'd move much of the code into JS to keep the current behavior) and make it easier to do custom error handling.

@ide

@ide Hi. I would very much appreciate such an API. In the mean time is there a way to prevent an production app from crashing on any random JavaScript exception?

This would be great for adding something like Bugsnag to report exceptions when apps are in production.

Edit: In fact, I think ErrorUtils.setGlobalHandler((err, isFatal) => { ... }); might do the job here.

We're looking to log something anytime there is an error, so we can catch bugs early. This would be very useful.

would be definitely useful!:+1:

@ide

@ide, what is the current recommended approach (or hack) for custom handling of global errors?

You could either hook into the native layer or monkeypatch the JS ExceptionsManager.

See ErrorUtils.setGlobalHandler: https://github.com/facebook/react-native/blob/master/Libraries/JavaScriptAppEngine/Initialization/InitializeJavaScriptAppEngine.js#L87

Is it a bad idea to set my own global error handler?

My scenario was to

Report exception to Sentry
Possibly reload the bridge to avoid being stuck in the error state

@ajwhite

Hi @ajwhite. Any luck completing the 2 points you mentioned?

@ide

Here: https://github.com/facebook/react-native/blob/d33b554f5d4bb7856cf2fc21175bab23d8225fe4/packager/react-packager/src/Resolver/polyfills/error-guard.js

var ErrorUtils = {
  _inGuard: 0,
  _globalHandler: null,
  setGlobalHandler: function(fun) {
    ErrorUtils._globalHandler = fun;
  },
//...

'setGlobalHandler' would overwrite a lot of the RN behaviour (eg. RedBox in development). Understanding that we could just monkey patch globalHandler, the "" seems alarming. So maybe an API like addGlobalHandler, so that we could add custom handler without breaking the default behaviour and and without messing with "internal" variables ? @ide @satya164

In production mode I call setGlobalHandler with my own handler, which does the two things listed above -- logging to sentry & reloading the bridge. Seems to work just fine.

@ajwhite

@ajwhite Cool. How do you reload the bridge? Would really appreciate it if you could share a gist or something.

@ajwhite

@ajwhite And you have a DEV check I suppose?

add getter as public api for ErrorUtils._globalHandler

This issue appears to have been solved by #5575. Closing this issue out for now.

The ErrorUtils.setGlobalHandler works great when the app's process is attached to the debugger (regardless if in debug / release bundle): I see a red screen with the error message, and my own custom handler is called fine.

But how do I handle errors for production apps, where a debugger won't be attached? When a debugger isn't attached and a crash occurs, the app doesn't show a red screen and just closes the app and goes to the home screen. In this case, my custom handler isn't called at all.

(Specifically describing the flow for iOS bundled app here)

Hi, I'm fairly new to both RN and javascript. I've put the following into my code... It catches errors and warnings in an array before reporting them as normal to the console.

It sits at the top of my main.js file. It seems to work, but is this a terrible idea?

const orig_console_warn = console.warn;
const orig_console_error = console.error;

let errors = [];
let warnings = [];

console.warn = function() {
  warnings.push(arguments);
  orig_console_warn.apply(console, arguments);
};

console.error = function() {
  errors.push(arguments);
  orig_console_error.apply(console, arguments);
};

I then periodically clear the array and send the data to some reporting system.

@jlo1

@jlo1 Did you ever find a solution for non-debug mode?

I'm pretty sure that global.ErrorUtils.setGlobalHandler works in production mode too on Android, fyi.

What about iOS? Is there a platform-agnostic way to do this?

I ended up trapping console.log, console.info, console.warn and console.error and writing the data to an in-memory buffer that I can view in my app. I also send error and warn messages to a server that records the data so I can see error from my clients in one central place.

iOS
  RCTSetFatalHandler(^(NSError *error) {
    [Bugly reportError:error];
    
     [rootView.bridge reload];
  });

Navigation Menu

Repository navigation

[JS] JS API for global handling of unhandled exceptions #1194

9 remaining items

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

[JS] JS API for global handling of unhandled exceptions #1194

Description

Activity

d-vine commented on Jun 11, 2015

JoeStanton commented on Jul 20, 2015

richardgill commented on Jul 30, 2015

despairblue commented on Sep 1, 2015

sjmueller commented on Sep 24, 2015

ide commented on Sep 24, 2015

mkonicek commented on Dec 15, 2015

atticoos commented on Dec 15, 2015

qbig commented on Jan 26, 2016

qbig commented on Jan 27, 2016

atticoos commented on Jan 27, 2016

qbig commented on Jan 27, 2016

qbig commented on Jan 27, 2016

9 remaining items

jsierles commented on Mar 20, 2016

jlo1 commented on Apr 12, 2016

npomfret commented on Jun 3, 2016

GeoffreyPlitt commented on Aug 26, 2016

antoinerousseau commented on Aug 27, 2016

GeoffreyPlitt commented on Aug 28, 2016

npomfret commented on Aug 29, 2016

nsyujian commented on May 31, 2018

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions