Lucas WintherandClaude Opus 5
f20a220dae
Rent every month, a subscription every 28 days, and a phone bill every 30 days whose clock RESTARTS when its data cap is hit early. A recurring cost projects EXPECTED charges forward; confirming one writes a real Purchase. The fold now carries two balances per post per month: `remaining`, untouched by this feature, and `projected`, which subtracts commitments that have not been paid yet. The data-cap behaviour is not a feature of its own. Under `lastCharge` anchoring the next occurrence is measured from the confirming purchase's OWN date, so confirming a slot early rebases the series — and two-stage confirmation already records that date. The domain never learns what a data cap is. That collapse is most of why this design is small: three recurrence kinds and one anchoring field, not a list of special cases. Two consequences worth not re-litigating. `everyNMonths` carries no day, because rent occurs IN September and IsoDate already permits "YYYY-MM" — which keeps day arithmetic out of the commonest case. And `amount` is a single mutable Money with no dated series, safe ONLY because confirmed purchases hold what was actually paid; under projection-only it would destroy history. Occurrences are computed, never stored. `upToMonth` comes from the caller, so src/domain/ stays clock-free. Schema 7. 651 tests, tsc clean, build green. Four defects were found by review rather than by the suite, each reachable and each invisible to a passing test: - Creating a cost then switching its unit stored a month-only startDate on a day-granular kind, which threw out of the fold and took every money route down. Two clicks. The validators checked date SHAPE where the UI checked VALIDITY, so a calendar-impossible "2026-09-31" survived a second round. - Confirming a future occurrence recorded today against a slot more than one cycle out, which walks the series backwards. Same crash, introduced by the change that closed a spec gap. - Editing a confirmed purchase's date in the ordinary purchase dialog — an act with nothing to do with recurring costs — could do the same thing, and the dialog swallowed the refusal so a save appeared to silently do nothing. - Import accepted a splitMode the fold would silently read as "fixed", turning intended percentages into absolute amounts. AGENTS.md §3 held throughout: negatives, percentages past 100 and non-summing splits are all still accepted, deliberately. Design: docs/specs/2026-09-03-recurring-costs-design.md Plan: docs/plans/2026-09-03-recurring-costs.md Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
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.mdandGEMINI.mdpoint 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.