[BUG] setTimeout fires incorrectly when using chrome debug

[Thomas101]

Hey,

I've found an issue that means when you're running on an iOS device and debugging in chrome setTimeouts can fire in the wrong order. If you place the following code block into a fresh app and run it you should get the error...

  componentDidMount:function() {
    this.runTest()
  },

  test:function(cb) {
    var aFired = false
    var bFired = false
    var aExpected = new Date().getTime()+130
    var bExpected = new Date().getTime()+500
    console.log('Schedule A to fire @' + aExpected)
    console.log('Schedule B to fire @' + bExpected)

    var a = setTimeout(() => {
      var now = new Date().getTime()
      console.log('A fired', now, now - aExpected)
      aFired = true
      if (bFired) { console.log('ERROR: b fired early'); return;
      }
      if (aFired && bFired) { cb() }
    }, 130)
    var b = setTimeout(() => {
      var now = new Date().getTime()
      console.log('B fired', now, now - bExpected)
      bFired = true
      if (!aFired) { console.log('ERROR: A not fired'); return;
      }
      if (aFired && bFired) { cb() }
    }, 500)
  },
  runTest:function() {
    this.test(() => {
      setTimeout(() => {
        this.runTest()
      }, 500)
    })
  },

On the console you'll get something like...

index.ios.js:25 Schedule A to fire @1448977966848
index.ios.js:26 Schedule B to fire @1448977967218
index.ios.js:30 A fired 1448977966754 -94
index.ios.js:38 B fired 1448977966755 -463
index.ios.js:25 Schedule A to fire @1448977966902
index.ios.js:26 Schedule B to fire @1448977967272
index.ios.js:30 A fired 1448977966806 -96
index.ios.js:38 B fired 1448977966806 -466
index.ios.js:25 Schedule A to fire @1448977966951
index.ios.js:26 Schedule B to fire @1448977967321
index.ios.js:30 A fired 1448977966835 -116
index.ios.js:38 B fired 1448977966835 -486


index.ios.js:25 Schedule A to fire @1448977966983
index.ios.js:26 Schedule B to fire @1448977967353
index.ios.js:38 B fired 1448977966871 -482
index.ios.js:40 ERROR: A not fired
index.ios.js:30 A fired 1448977966871 -112
index.ios.js:32 ERROR: b fired early

... with the first 3 firing correctly and the last one incorrectly. I believe this bug is also what is causing issue #1693 as one of the setTimeout functions sometimes fires early in touchableHandleResponderGrant

[facebook-github-bot]

Hey Thomas101, thanks for reporting this issue!

React Native, as you've probably heard, is getting really popular and truth is we're getting a bit overwhelmed by the activity surrounding it. There are just too many issues for us to manage properly.

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[christopherdro]

@Thomas101 Try taking a look at https://facebook.github.io/react-native/docs/timers.html#timermixin at the last paragraph:
We strongly discourage using the global setTimeout(...) and recommend instead that you use this.setTimeout(...)

[Thomas101]

Thanks @christopherdro, we've been using that wherever possible but some of the built in react functionality uses plain old settimeout which is where the bug raised its head initially

[ide]

@Thomas101 Thanks for your detailed investigation and write-up. RN should implement timers correctly. In fact if I'm reading your code and logs correctly, it looks like the timeout arg is ignored as events A and B run at almost the same time. cc @sahrens

[Thomas101]

Those were the logs that came out, you should get similar results if you run it yourself. This is purely speculation as I haven't looked at the implementation, but as it only happenens when running the chrome debugger and using the device, did wonder if it could be a time drift issue between my Mac and ipad?

[satya164]

@christopherdro Also not possible to use it when using the ES6 class syntax. Need to manually cleanup ofc.

[sahrens]

Not sure who owns timers these days - maybe @tadeuzagallo or @nicklockwood ? Also cc @dmmiller because we want to be consistent on iOS and android.

[aleclarson]

I've experienced this while "Debug in Chrome" is active. setTimeout fires very early.

Has it been confirmed that TimerMixin avoids this issue?

I thought TimerMixin only helps with cleanup in componentWillUnmount?

[Thomas101]

Hi @aleclarson using the TimerMixin still has the same problem as this uses setTimeout behind the scenes.

[aleclarson]

Who works on the debugger-proxy packager endpoint? Is there a hack related to setTimeout that involves accounting for socket latency? I can't imagine how else setTimeout could be acting so strangely.

[PaulBGD]

Go vote for this issue so that the developers can see that it's important: https://productpains.com/post/react-native/settimeout-fires-incorrectly-when-using-chrome-debug/

[sahrens]

I don't know much about our chrome integration or why it would cause a difference in timer behavior - @frantic or @tadeuzagallo?

[aleclarson]

Would it be worth implementing a native shim for setTimeout and clearTimeout?

[satya164]

Any updates on this?

[satya164]

So, I did a some small test on this,

var start = performance.now(); console.log(performance.now(), start); // 751855.6900000001 492872.2
var start = performance.now(); setTimeout(() => console.log(performance.now() - start), 1); // 345195.46

This is super weird. The value of performance.now() is vastly different than when it's assigned to a variable. SImilar results for Date.now().

No wonder setTimeout executes instantly even if you give a timeout of 10 seconds.

cc @vjeux @dmmiller @nicklockwood

[vjeux]

[meta-discussion] At this point, there is a good repro case (thanks @Thomas101, that's really awesome) and no clear owner (as everyone is cc-ing other people). The way forward is to get someone to dig into the internals and figure out what's going on. It doesn't have to be a Facebook employee, thankfully the entire part of this stack is open source and anyone can try and figure out what's going on.

I suggest that if you are affected by this issue and have some time to spare, try to dig in and figure out what's going on.

[marcosinigaglia]

I think the release 0.25-rc solve the problem.

[Abhay-Joshi-Git]

I am using 0.28.0. It looks like logging in chrome with this.setInterval is not working still. I faced the issue for Android.

[martinarroyo]

Same as @Abhay-Joshi-Git here as well (using plain setTimeout in a function outside a React component). For a timeout of 4000 ms it fires immediately. (RN 0.28.0 running on Android device). When Chrome Debugging is disabled it works as expected.

[nihgwu]

I'm using RN0.29RC0 and facing the same problem, onLongPress fires immediately while Debug JS Remotely enabled

[marcshilling]

Happening to me with RN 28....setTimeout are firing immediately.

[greatbsky]

RN0.29 fires immediately while Debug JS Remotely enabled

[matt-oakes]

Will this cease to be a problem once this issue is implemented? #8641

[nambrot]

fwiw, on Android, when in Debug with Chrome, setTimeout does not fire at all

[lacker]

It looks like this is fixed as mentioned in #9436 . It kind of seems like there's a bunch of different issues being discussed here so if similar things continue to occur perhaps it would be easier to open a new issue. Anyway I am going to close this one.

[tomasfrancisco]

I'm not certain that the issue that is reported on this thread is resolved.
I'm getting the same behavior as described by many of you.
One way to get things done and testable was to set the timers to a time less than 2 seconds, but when the app gets bigger it will be unbearable to test it.

RN0.42.0

[jesseditson]

Also experiencing this, not sure why this bug is closed. Shall we file a new one? Seems like that's what's being suggested by @lacker, is that just to keep noise down? Is there any reason to believe a prior patch would have fixed this? (It's unclear to me if this was ever fixed.)

[lucasbento]

The same thing happened here with RN 0.44.0 running on Android.

[Odinvt]

For the people who are still facing this issue ! which is the case for us on RN 0.44.0 on Android :

We found indeed that the problem was related to the device time not being exactly as the time on the chrome remote debugger machine. This is due to the React Native javascript setTimeout function calling the native Timing.createTimer method with a Date.now() parameter which is not the same as the native side's time when in remote js debug mode (where the javascript execution environment is the chrome browser or whatever debugger you're using) as you can see in JSTimers.js#L93.

So, the solution for us was 1 of the following :

• Either set the time of the device to be exactly as the remote debugging machine's time using ADB
• Or compensate for the time difference between the native side and the remote js side

We chose the second solution as the first one wasn't suited for our needs so we created a package called React Native Timer Native (I know, i'm not so good when it comes to naming things ^^') which is a fork of React Native Timer.

What it does --as a stupid hack-- is simply call a native method (when in dev mode) with the current javascript timestamp, then the native method gets its current timestamp using System.currentTimeMillis(), calculates the difference and returns it back to javascript, then the js package just adds that to whatever duration you passed to timer.setTimeout .

The device time must be in the future compared to the remote debugging machine time otherwise it doesn't work properly

It does get the timeouts executed with a decent precision (still need to substract the time that the bridge takes to call the native method so any inputs are welcome ;) ).

[hansfpc]

Same issue here (Using RN 0.45). I have to disable 'Debug JS remotely' :(

[MrToph]

Still an issue in 0.46.3, can we reopen this?

[caltv]

I'm also seeing this with the iOS simulator, and my machine has the same time as the Simulator...disabling 'Debug JS remotely' fixes it

[nicotroia]

For me, the setTimeout will wait until a re-render happens. So you have to touch the screen or scroll the page in order to fire the handler (assuming the time has passed). Disabling remote debugging makes it work as normal

[alpfilho]

still an issue in 0.46.4

[dave-irvine]

Still an issue on 0.47.x as far as I can tell

[emusgrave]

@Odinvt Did you consider integrating your library into a PR for the core RN library? I'm curious if the team would accept it as a solution for this issue.

[Odinvt]

@emusgrave I thought about it and I would love to, but I don't think that the PR will be merged because first of all, it's an ugly hack and second of all, it's not a modification of react native's source code, it's only a modification of another package ( React Native Timer ) which would force devs to use the package's overridden methods instead of the classic JS setTimeout and setInterval methods...

The source code is there, we've been using it for 4 months in our dev env for our projects and it's proven its worth. I encourage anyone who has the time to make those changes in RN's source code and submit a PR to do so, I think that the idea is there but the code still needs some refactoring and tests should be written. I hope you're all having fun creating stuff with RN as I know I do <3

[kesha-antonov]

RN 0.50 Same issue

[ahmb84]

Same issue from RN 0.50.3

[loveky]

any update on this? just spent about 1 hour and see this issue... 😞

[jacklovepdf]

close the debugger model

[Vishal-vash]

I had similar issue using onLongPress with debugger open and it fires the event as onPress , So onLongPress also don't work accurately in debugger mode similar to setTimeout/setInterval

[dhirendrarathod2000]

RN 0.53
Not working

[fatfatson]

sync your emulator and host' time by:

adb shell su root date $(get-date -format MMddHHmmyyyy.ss)

[Sharcoux]

get-date -> unknown command.

I had better luck with:

adb shell su root "date `date +%m%d%H%M%Y.%S`"