# Time Tools

Work with dates, time zones and recurrences locally in the browser.

Time Tools is a standalone local-first application in the [add·ideas Toolbox](https://git.add-ideas.de/lotobo/toolbox-portal). Inputs are processed in the browser and are not uploaded.

## Version 0.1 scope

- Exact signed epoch conversion through nanosecond precision
- IANA-zone comparison, skipped/ambiguous local-time resolution and transition inspection
- Side-by-side wall-clock and elapsed-duration arithmetic
- Bounded 5/6/7-field cron and strict RFC 5545 RRULE occurrence previews
- Weekend/explicit-holiday business-day arithmetic and escaped UTC iCalendar event export

Named-zone results use the IANA data supplied by the browser runtime and can therefore vary with browser versions. ECMAScript Temporal does not represent leap seconds. The business-day calculator excludes weekends and only the holiday dates supplied by the user; it does not infer regional calendars. See [docs/ARCHITECTURE.md](docs/ARCHITECTURE.md) and [docs/PRIVACY-SECURITY.md](docs/PRIVACY-SECURITY.md).

## Development

Requires Node.js 22 and npm 11.

```sh
npm ci
npm run check
npm run test:browser
```

## Release

`npm run release:artifact` creates a deterministic `release/time-tools-0.1.0.zip` and checksum sidecar.

## Licence

GPL-3.0-or-later. Runtime dependencies retain their own licences; see [THIRD_PARTY_NOTICES.md](THIRD_PARTY_NOTICES.md).