react-native: new Date() bug

Is this a bug report?

Yes

Have you read the Contributing Guidelines?

Environment

react-native -v: react-native-cli: 2.0.1 react-native: 0.46.4
node -v: v7.10.0
npm -v: 4.2.0
yarn --version:

Then, specify:

Target Platform: iOS 11.0

Development Operating System: macOS Sierra

Build tools: xCode9 beta

Steps to Reproduce

Not sure if it’s a react-native issue or iOS, but i’m setting a new Date(‘string’) -the string comes from the server- and it converts to a Date on iOS emulator, however when I run on device it becomes an invalid date (as I console logged on xCode).

here the logs:

the log scheme: console.log(‘string identifier’, ‘new Date(string)’, date string from server);

log commands: console.log(‘dtini’, dataInicio, this.props.programacaoLazer[i].data_inicio); console.log(‘dtfim’, dataFim, this.props.programacaoLazer[i].data_fim); console.log(‘dtselec’, this.state.dataSelecionada); log on emulator: dtini Tue Sep 05 2017 10:40:00 GMT-0300 (-03) 2017-09-05 10:40:00 dtfim Tue Sep 26 2017 13:18:00 GMT-0300 (-03) 2017-09-26 13:18:00 dtselec Tue Sep 05 2017 15:29:06 GMT-0300 (-03)

log on Xcode running on device: 2017-09-05 15:21:50.326 [info][tid:com.facebook.react.JavaScript] ‘dtini’, Invalid Date, ‘2017-09-05 10:40:00’ 2017-09-05 15:21:50.326 [info][tid:com.facebook.react.JavaScript] ‘dtfim’, Invalid Date, ‘2017-09-26 13:18:00’ 2017-09-05 15:21:50.327 [info][tid:com.facebook.react.JavaScript] ‘dtselec’, Tue Sep 05 2017 15:18:37 GMT-0300 (-03)

About this issue

Original URL
State: closed
Created 7 years ago
Reactions: 9
Comments: 16 (2 by maintainers)

Most upvoted comments

We’ve faced the same problem. For some reason JavaScriptCore doesn’t take “YYYY-MM-DD HH:MM:SS” format as a constructor param, (it does recognise “YYYY-MM-DD”, and another format mentioned below) Using moment.js might be an overkill, I wrote a tiny function that addresses this issue:

const jsCoreDateCreator = (dateString) => { 
  // dateString *HAS* to be in this format "YYYY-MM-DD HH:MM:SS"  
  let dateParam = dateString.split(/[\s-:]/)  
  dateParam[1] = (parseInt(dateParam[1], 10) - 1).toString()  
  return new Date(...dateParam)  
}

+46

SahRckr on Mar 2, 2018

Same. Trying new Date('2017-11-7, 6:37 pm') with debugger off results in Invalid Date with debugger on result is: Tue Nov 07 2017 18:37:00 GMT+0200 (EET)

+13

nezaidu on Dec 13, 2017

yes i’m using chrome debugger on emulator.

i have fixed it by declaring the new Date as:

const dataInicio = new Date( parseInt(atividade.data_inicio.slice(0,4)), parseInt(atividade.data_inicio.slice(5,7)) - 1, parseInt(atividade.data_inicio.slice(8,10)), parseInt(atividade.data_inicio.slice(11,13)), parseInt(atividade.data_inicio.slice(14,16)), 0, 0 );

However it`s funny that it works on emulator but not on device

Gigasz on Sep 5, 2017

Are you using the Chrome debugger? (Make sure you aren’t using it for Date-related operations, V8 is different from JSC.)

ide on Sep 5, 2017

I suggest this:

Test correct time.
Change the Device time.
Rebuild the application
Test time again.

JSCore is not native to Android, It’s highly likely that the rebuilding might fix your problem.

SahRckr on Aug 30, 2018

I ended up with a slight modification of @SahRckr’s method to handle UTC dates.

This handles the format 2018-07-18 15:27:55 UTC. Note that it will break for anything non-UTC.

const parseUTCDate = dateString => {
  const dateParams = dateString.replace(/ UTC/, '').split(/[\s-:]/)
  dateParams[1] = (parseInt(dateParams[1], 10) - 1).toString()

  return new Date(Date.UTC(...dateParams))
}

connorpaulstauffer on Jul 18, 2018

@SahRckr Rebuilding might solve the problem but I cannot rebuild the application. I am developing a feature in which if time on user’s device is incorrect (Criteria is if the time difference between mobile device time & time sent from server is more than 15 minutes),then I redirect him to Date & Time Settings in Android

Udbhav12 on Aug 30, 2018

That’s because react-native run javascript code using JavaScriptCore engine and it behaves like @Gigasz said, if anyone want to test code same way it would run in a real device, can install and use rhino

yalopov on Jan 22, 2018

For me helped this: moment( date & time , "YYYY-MM-DD hh:mm a").format("YYYY-MM-DDTHH:mm:ss") You can try to see it in Safari -> development->agent->IOS device On IOS work good!

Resmedia on Oct 6, 2017