Lucas Winther
8c3dbafc86
Nine tasks. One through three are the domain and run in strict order: the clamped month step, the type and signature changes, then the split walk. Four (migration), five (validation) and six (the band) each depend on three. Seven (the split editor) is independent. Eight (the purchase dialog) needs seven and five. Nine is docs and demo data. Task three carries two deletions that belong tidily to tasks five and six. They are done early because deleting wouldAdvancePast breaks compilation in both files, and a task that cannot run its own suite cannot be reviewed. Every expected value was checked by hand rather than derived from the implementation: the 30-day step from 2026-09-12 lands on 2026-10-12 then 2026-11-11; 31 Aug + 6 months clamps to 28 Feb 2027; and 31 Jan + 2 months is 31 March, which only holds if the clamp measures from the original day instead of stepping month by month. That last one is the trap in Task 1 and it has its own test. Flagged as the known risk: making SplitEditor generic touches the purchase dialog, which is unrelated to recurring costs. The claim that PurchaseDraft satisfies SplitTarget structurally is checkable by tsc alone and should be verified before the rest of that task is written.
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.