Node: NodeJS reports incorrect time zone for Brazil

[albertyw]

• Version: v13.0.1
• Platform: Darwin 18.7.0 Darwin Kernel Version 18.7.0: Tue Aug 20 16:57:14 PDT 2019
• Subsystem: N/A

Node is reporting the wrong time zone for Brazil after its cancelled daylight savings change on November 2.

Reproduction:

var process = require('process');
console.log('ICU version: ' + process.versions.icu);

var options = {
    timeZone: "America/Sao_Paulo",
    year: 'numeric', month: 'numeric', day: 'numeric',
    hour: 'numeric', minute: 'numeric', second: 'numeric',
    timeZoneName: 'short'
};

var formatter = new Intl.DateTimeFormat([], options);

var UTCTimeBefore = new Date(new Date().toUTCString());
var UTCTimeAfter = new Date(UTCTimeBefore.getTime() + (7 * 24 * 60 * 60 * 1000));
var UTCTimeAfter = new Date(UTCTimeBefore.getTime() + (30 * 24 * 60 * 60 * 1000));
var localTime = formatter.format(UTCTimeBefore);
console.log('Should be GMT-3')
console.log(localTime);
var localTime = formatter.format(UTCTimeAfter);
console.log('Should also be GMT-3')
console.log(localTime);

Outputs:

ICU version: 64.2
Should be GMT-3
11/1/2019, 7:19:15 PM GMT-3
Should also be GMT-3
12/1/2019, 8:19:15 PM GMT-2

I believe this is because node v13.0.1 depends on ICU version 64.2 which includes tzdata 2019a. However, brazil's updated daylight savings was added in tzdata 2019b, which requires a minimum ICU version of 65.1.

[targos]

Tracking issue for update to ICU 65.1: https://github.com/nodejs/node/issues/29540

[apaprocki]

Time zone data files are updated independently of ICU. You do not need to tie updating time zone data with upgrading ICU, which could have other consequences.

To update the existing ICU 64 .dat file:

• decompress the icudt64l.dat archive
• download the 2019c files from https://github.com/unicode-org/icu-data/tree/master/tzdata/icunew (le little-endian, and be big-endian, depending on platform)
• follow the instructions at http://userguide.icu-project.org/datetime/timezone to patch the .dat file for all four time zone resource files (the resource files must be in the current directory):
  > icupkg -a <resourceFile> icutdt64l.dat
• if you want, verify that there is only one of each file in the .dat file using the -l list option
• if you want, verify that after you -x extract the file, the shasum matches what you intended to patch
• compress the icudt64l.dat archive as before

To test the patched file works...

Existing Node v12.13.0 release:

$ node -e 'console.log(Intl.DateTimeFormat("en-US", { dateStyle: "long", timeStyle: "long", timeZone: "America/Sao_Paulo" }).format(Date.UTC(2019, 10, 4, 23)))'
November 4, 2019 at 9:00:00 PM GMT-2

After patching .dat file:

$ node -e 'console.log(Intl.DateTimeFormat("en-US", { dateStyle: "long", timeStyle: "long", timeZone: "America/Sao_Paulo" }).format(Date.UTC(2019, 10, 4, 23)))'
November 4, 2019 at 8:00:00 PM GMT-3

If it helps, the shasum of the v12.13.0 release and patched files:
Release: 2b681d53f193f714db86b038176da6866f8d5afd icudt64l.dat
Patched: 7317c1d424812d9ef1ed318e70db7ed27b93853c icudt64l.dat

[MylesBorins]

/cc @srl295

[srl295]

@apaprocki would you like to make a PR to update tools/icu/ with a readme about how to do this? Good instructions. I would add that you can have the updated tz data outside of node.js, without recompiling, i will have to add detailed instructions for that.

additionally, process.versions.tz will return the tz version such as 2019b

[apaprocki]

I would add that you can have the updated tz data outside of node.js, without recompiling, i will have to add detailed instructions for that.

I specifically left that part out because Node does not currently build with the external directory enabled. If someone decides on an installation path where Node should look for updated ICU time zone data files, I can include that text as well. (e.g., PREFIX/share/icu/tzdata?)

Also, current ICU (65.1) does not expose the ..._ENV_VAR override for the external time zone resource directory the same way that it does for the whole ICU data file directory. I had to add patch in support for that to ICU to make it so that both data file directories could be properly relocatable with the same (in my case) environment variable. I'll look into sending that patch upstream.

[srl295]

I meant NODE_ICU_DATA or --icu-data-dir - but you’re right, the tzdata specific option may not be enabled by default.

[apaprocki]

@srl295 I filed ICU-20895 and opened the pull request for the environment variable.

[MylesBorins]

I've backported to 12.x and 10.x. For now I didn't update 8.x. @nodejs/lts thoughts?

[leonetosoft]

I have the same problem, I need to set the time zone for the America/Campo_Grande node, I already changed the environment variable (TZ) but it still doesn't work ...

[kirliam]

@leonetosoft I had the same problem, and the workaround I'm using is the "set-tz" package. Install it and add in the first lines of your app:

const setTZ = require('set-tz');
setTZ('America/Bahia');

[srl295]

@kirliam @leonetosoft is this on Windows? That seems to be the only place it would make a difference, all set-tz does is set process.env.TZ besides on Windows.

Edit: i misread, set-tz may not even do that. Can you show me some code that isn't working and tell me the version and OS?

[emarcelino3]

I substitute timeZone: "America/Sao_Paulo" by timeZone: "-03:00".

work fine to me

[kirliam]

Yes, it's Windows!

On Thu, May 7, 2020, 11:52 Steven R. Loomis [e-mail]
wrote:

@kirliam https://github.com/kirliam @leonetosoft
https://github.com/leonetosoft is this on Windows? That seems to be the
only place it would make a difference, all set-tz does is set
process.env.TZ besides on Windows.

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