https://github.com/kshetline/tubular_time_tzdb I spoke about this new tz compiler a while back, when I released my @tubular/time date-time library, but the compiler was only at the level of a tool for personal use, without decent documentation or all of the features I’d want for a general-purpose utility. At first this compiler only produced data for use with @tubular/time, but now it can output zoneinfo/zic binaries too. One nice feature is that this tool, by default, reaches right out to https://www.iana.org/time-zones/ for data, with no need to download a release before using the compiler. There’s a JavaScript/TypeScript API and a CLI command. I’ll show the CLI command help, just so people can get an idea of the options available. Anyone can go to https://github.com/kshetline/tubular_time_tzdb for more info. npm install -g @tubular/time-tzdb Usage: tzc [options] [output_file_name_or_directory] Downloads and compiles IANA timezone data, converting to text, zoneinfo binary files, or @tubular/time-compatible data. Options: -v, --version output the version number -5, --systemv Include the SystemV timezones from the systemv file by uncommenting the commented-out zone descriptions. -b, --binary Output binary files to a directory, one file per timezone -B, --bloat Equivalent to the zic "--bloat fat" option. -f Filter out Etc/GMTxxx and other timezones that are either redundant or covered by options for creating fixed-offset timezones. -i Include leap seconds in binary files. -j, --javascript Output JavaScript instead of JSON. --large Apply presets for "large" timezone definitions. --large-alt Apply presets for "large-alt" timezone definitions. --list List available tz database versions. -m Round all UTC offsets to whole minutes. -n, --no-backward Skip the additional aliases in the backward file. -o Overwrite existing file/directory. -q Display no progress messages, fewer warning messages. -R, --rearguard Rearguard mode (skip vanguard features like negative DST). -r Remove 'calendar rollbacks' from time zone transitions -- that is modify time zone data to prevent situations where the calendar date goes backwards as well as the hour and/or minute of the day. -p, --packrat Add additional timezones from the backzone file. -s <zone-id> ID/name for a single timezone/region to be rendered. --small Apply presets for "small" timezone definitions. -t, --typescript Output TypeScript instead of JSON. --text Output (somewhat) human-readable text -u, --url <url> URL or version number, such as '2018c', to parse and compile. Default: https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz -V, --vanguard Vanguard mode (use vanguard features like negative DST). -y <year-span> <min_year,max_year> Year range for explicit time zone transitions. Default: 1850,2050 -z <zone-info-dir> Validate this tool's output against output from the standard zic tool stored in the given directory. (Validation is done before applying the -r option.) -h, --help display help for command -, Use dash by itself to output to stdout.