Lucas Winther de333685a2 feat(domain): day arithmetic without Date
Recurrences of 28 and 30 days do not align to months, so the domain needs
day-level maths for the first time. It gets it the way months.ts does: an
integer ordinal, no Date anywhere. A Date would make 2026-03-29 a different
instant per timezone while being the same day everywhere, and a 28-day step
must not gain or lose a day at a DST boundary.

Hinnant's days_from_civil, which shifts the year to start in March so the leap
day is the last day rather than an insertion, removing every special case.

No isDayGranular export: nothing in the plan consumes it, later tasks branch
on a recurrence kind and import validation uses a regex directly.
2026-09-03 03:34:32 +02:00

Budget 2.0

A personal budgeting PWA. Envelope-style monthly budgets with rollover, split purchases, finance plans, multi-currency, and JSON/ODS export. All data lives in your browser — there is no server and no account.

Development

bun install
bun run dev               # dev server with hot reload, on :3000
bun test                  # run the test suite
bun run build             # production build into dist/

Self-hosting with Docker

docker build -t budget2 .
docker run --rm -p 3000:3000 budget2

To serve from a subpath, build and run with BUN_PUBLIC_BASE_PATH:

docker build -t budget2 --build-arg BUN_PUBLIC_BASE_PATH=/budget/ .
docker run --rm -p 3000:3000 -e BUN_PUBLIC_BASE_PATH=/budget/ budget2

GitHub Pages

Pushing to main builds and deploys to Pages automatically, using /<repository-name>/ as the base path. Enable Pages with "GitHub Actions" as the source in the repository settings.

Your data

Everything is stored in this browser's IndexedDB. Export regularly from Settings → Your data: the JSON export is both your backup and how you move your budget to another device.

Both destructive actions there — Import, and "Reset everything" — download a backup of your current data before replacing it, and abort if that download fails. Reset puts the app back to a brand-new install: the three starter posts, the DKK/USD/EUR currency table, this month at zero income, no purchases.

Known limitations

  • Data is per-browser. There is no account and no sync. If you clear this browser's site data, or move to a different browser or device, your budget is gone unless you exported it first. The JSON export is not just a nice-to-have backup — it is the only way to move a budget between devices.
  • Installing and offline use are unverified. The manifest ships the SVG plus 192×192 and 512×512 PNG icons, and the service worker demonstrably installs, activates and precaches every asset — but nobody has yet confirmed that Chrome offers its "Install app" prompt, or loaded the app with the network actually cut. It works as a regular tab regardless.

Documentation

  • docs/ARCHITECTURE.md — layers, data flow, and why the non-obvious choices are what they are.
  • docs/PRODUCT.md — who this is for and what must never break.
  • AGENTS.md — the rules for changing this codebase, and the test that catches each one when broken. CLAUDE.md and GEMINI.md point at it.
  • docs/DECISIONS.md — an index of the choices that shaped the app, and what each was chosen over.
  • docs/TODO.md — what is still queued.
  • docs/specs/ — one design document per piece of work, each recording the alternatives that were rejected.
  • docs/plans/ — task-by-task implementation plans.
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