[TimezoneReactiveUtils] Timezone seems to be reversed

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Vincent Klijs

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[TimezoneReactiveUtils] Timezone seems to be reversed

Question

Reactive

Forge

OutSystems 11

Timezone

Application Type

Reactive

Service Studio Version

11.14.16 (Build 60354)

Greetings, due to a issue I had I installed this component ... but it doesn't seem to work as expected.

In an expression, I used the function GetCurrentTimezoneOffset() but to my surprise it returned -120 whereas I would have expected it to return 120.

Because of this, I did some more digging, and to my surprise, when I created a expression that explictely creates a datetime, and use the ConvertDateTimeByTimeZoneOffset function it actually end up in less than UTC time, instead of a later timezone ( as mentioned before, I'm with DST currently in +2h )

To be preciese, the following expression

FormatDateTime(NewDateTime(2022,5,20,10,0,0), "yyyy MMM d HH:mm")+NewLine()+
FormatDateTime(ConvertDateTimeToUTC(NewDateTime(2022,5,20,10,0,0)), "yyyy MMM d HH:mm")+NewLine()+
FormatDateTime(ConvertDateTimeByTimezoneOffset(NewDateTime(2022,5,20,10,0,0),TextToInteger(GetCurrentTimezoneOffset())),"yyyy MMM d HH:mm")

leads to this output

Perhaps I'm using it wrong ( I am fairly new to outsystems .. so this is not unthinkable ) ... but if so I have to say that it has been implemented rather counter intuitive. If I am using it right, then I think there is an issue ...

Hope to hear from you soon.

Kind regards,

Vincent

20 May

Kilian Hekhuis

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Solution

Hi Vincent,

I just published a new version, 1.0.3, that has the bug fixed. Could you please try and see whether it meets your expectations? Thanks in advance!

See solution in context

20 May

2 replies

Last reply 23 May

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Vincent Klijs

Hey Kilian,

ConvertDateTimeByTimezoneOffset now does work as expected! To be honest, I still find the value for GetCurrentTimezoneOffset counterintuitive ... but you yourself said the same thing. Thanks for the quick reply.

kind regards,

Vincent

23 May

Kilian Hekhuis

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MVP

Replying to Vincent Klijs' comment on 23 May 2022 07:26:17

Yeah, I would've done it differently, but too late to change it now without a breaking change to all existing code...

23 May

Kilian Hekhuis

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MVP

Hi Vincent,

There's a number of things to say here. First, GetCurrentTimezoneOffset just returns the JavaScript timezone offset, which is counterintuitive, as it is calculated by subtracting the local time from the UTC time. Since we are ahead of UTC, the result is negative. This is described here.

Secondly, there's an obvious bug in the ConvertDateTimeByTimezoneOffset code. The code first converts the date time to UTC, then adds the number of minutes to the UTC date time as returned by GetCurrentTimezoneOffset. As your example shows, this yields the wrong results.

I'll see if I can upload a new version shortly.

20 May

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Last reply 23 May

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Vincent Klijs

ah, so it's a bit of both ... a bit counter intuitive, but also a bug! Thank you for the quick reply, and perhaps it's usefull to add this javascript explanation to the documentation so it's clear that the offset is in fact inverted.

Anyway, knowing this, it is a usefull addition!

20 May

Kilian Hekhuis

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Replying to Vincent Klijs' comment on 20 May 2022 12:54:42

Agree with the documentation, but that's pretty lacking at the moment. I'll see if I can add something.

23 May

Kilian Hekhuis

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MVP

Solution