A confirmation is an ordinary Purchase, and the ordinary purchase dialog can
edit its date. Under lastCharge anchoring that date is what the walk measures
the next occurrence from, so moving it back more than a cycle made the walk
step backwards and throw out of foldBalances -- every month route, the year
view and the summary down at once, from an edit that never mentioned recurring
costs.
updatePurchase is the write that can invalidate an already-valid confirmation,
so it now asks wouldAdvancePast -- the same helper ExpectedBand asks before
offering a row -- and refuses the edit instead. The walk's throw is unchanged:
a step that lands backwards really is bad data, and this stops it being
created. A purchase with no source is not checked at all, and a source naming
a cost that no longer exists falls through.
PurchaseDialog was closing on save regardless of the outcome, with its
useMutate error rendered nowhere, so a refusal looked like a save that did
nothing. mutate now reports whether the write landed, and the dialog stays
open and shows the reason when it did not.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
setRecurringCostEndedFrom is the only place that keeps archived and
endedFrom paired, and endRecurringCost/restoreRecurringCost/the Ends column
already delegate to it — but updateRecurringCost still typed its `changes`
as Partial<Omit<RecurringCost, "id">> and Object.assign'd it, so a caller
passing either field alone would desynchronise the pair. No current call
site does this, so it was latent; excluding both keys from the accepted
type makes it impossible rather than merely unexercised.
Gap 2 (spec §10): endedFrom is typed as any IsoDate and the spec calls it
"cancellation", but Settings only ever wrote currentMonth — backdating or
forward-dating a cancellation was import-only.
Add an "Ends" column beside "Starts" in the Recurring costs table, edited and
validated the same way (isValidEndedFrom — no granularity rule, per §10, but
still refuses a calendar-impossible date like "2026-02-30"). Empty means "not
ended" and clears the cancellation.
Coherence rule: `archived` mirrors "endedFrom is set". setRecurringCostEndedFrom
is the one place that now enforces it — endRecurringCost and
restoreRecurringCost (the one-click row buttons) delegate to it, so the column
and the buttons can never leave a bill dimmed-but-live or ended-but-undimmed.
Also closes the same calendar-impossible gap in the JSON importer, which
checked endedFrom's shape but not its calendar validity, unlike startDate.
Gap 1 (spec §5): ExpectedBand only listed this month's occurrences, so a
lastCharge bill whose pending slot had rolled into next month (the phone-bill
flagship case) was not confirmable without navigating there first.
Extend the walk 12 months past the displayed month (occurrencesByMonth's own
upToMonth bound; foldBalances is untouched) and surface a "Coming up" group:
at most one row per recurring cost, its next unconfirmed occurrence. That row
confirms EARLY, so it records today rather than the future slot date — which
is exactly what rebases a lastCharge series — and shows both dates so the
owner can see what will be written. `today` is exported from src/store/index.ts
next to `currentMonth`, keeping the clock out of src/domain/.
expectedGroups() is the pure, exported core (pending/overdue/comingUp);
ExpectedBand renders it and still returns null when all three are empty.
requireStartDateGranularity (store/actions.ts) and its import-path twin
(export/json.ts) checked date SHAPE with a regex, not date VALIDITY, so
"2026-09-31" (September has 30 days) passed both and threw later out of
foldBalances instead of at the write boundary. isValidStartDate
(RecurringSection.tsx) had the same hole for a day-shaped value under
everyNMonths. Separately, monthOf's regex (domain/months.ts) was
unanchored at the end, so "2026-091" was silently read as September 2026.
Route day-shaped values through toDayOrdinal and month-shaped values
through monthOf (now anchored to accept only "YYYY-MM" or "YYYY-MM-DD" in
full, never a prefix) at all three write boundaries, converting whatever
they throw into each file's own error style.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
addRecurringCost and updateRecurringCost now reject a day-granular
recurrence (everyNDays/everyNWeeks) paired with a month-only startDate.
occurrencesOf hands startDate straight to addDays for those kinds, which
throws "Not a day-granular IsoDate" — reachable in two clicks by adding a
cost (always created as everyNMonths, startDate "YYYY-MM") and then
switching its unit in the dropdown without touching Starts.
updateRecurringCost checks the resolved pair (changes merged onto the
stored cost) on every call, not just one that touches recurrence or
startDate, since either field alone can break the pairing.
Also corrects endRecurringCost's doc comment: archiving does not hide a
recurring cost from the list, it dims it — the code already matches
PostsSection, only the comment was wrong (M6).
confirmOccurrence writes an ordinary Purchase: the slot it claims goes in
source.occurrenceDate, the date the money moved goes on the purchase, and the
two differ whenever a bill is paid off schedule. Splits are copied rather than
shared, so editing the purchase cannot rewrite the cost.
endRecurringCost sets endedFrom AND archived, because they do different jobs —
one stops the projection, the other only hides the row. Archiving alone would
leave a cancelled bill projecting forever. Neither touches a past occurrence,
so no historical figure moves.
requireRecurrence rejects n below 1 and non-integers rather than clamping.
The walk terminates only if every step advances, and the importer is not the
only write path.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
remaining is untouched: carriedIn + allocation - charges, exactly as before, so
no figure the owner has reconciled against their bank can move when they add a
recurring cost. projected runs beside it on its own carry, subtracting
unconfirmed occurrences as well.
Two invariants pin it, both tested. With no recurring costs the tracks are
identical in every month — that is the behaviour-preservation guard for every
dataset that exists today. Once a month's occurrences are all confirmed they
reconverge there, because a confirmation is an ordinary purchase counted in
charges and skipped by expected.
An unconfirmed occurrence in a PAST month therefore holds projected below
remaining forever. That is the honest reading — an unreconciled commitment —
and the month view surfaces the count so it is not silent.
Also required to typecheck once PostMonthFigures gains these fields:
- src/store/migrations.test.ts: delete the two @ts-expect-error directives
that stood over the "NO figure changes" guard test since Task 2. That test
is now green — the point of this task.
- src/ui/meterSegments.test.ts: the figures() test helper builds a complete
PostMonthFigures literal; default expected to 0, projectedCarriedIn to
carriedIn, and projected to remaining, matching its existing partial.X ??
style.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Recurrence is two orthogonal fields, not a list of special cases: a kind
(everyNMonths / everyNDays / everyNWeeks) and an anchoring (calendar /
lastCharge). The phone bill that recharges early when its data cap is hit is
everyNDays(30) anchored to lastCharge — the domain never learns what a data cap
is, because confirming the occurrence early already records the date.
Purchase.source pairs occurrenceDate (identity: which slot this claims) with
Purchase.date (truth: when the money moved). They differ whenever a bill is
paid off schedule, and lastCharge measures from the latter.
RecurringCost.amount is a single mutable Money with no RuleVersion-style
series. Safe only because confirmed purchases hold what was actually paid;
under projection-only it would destroy history.
The 6 -> 7 step writes an empty array and reads nothing. Decimals took 6.
`Settings.digits` replaces `CurrencyDef.digits`. Every amount rounds to it,
whatever its currency, and `digitsFor` is gone: the sixteen call sites read the
setting, and the domain functions that took a currency table purely to look
digits up take a `digits: number` instead. Schema 6.
The owner asked for this with the cost in front of them, and the cost is real:
a dataset mixing minor units cannot be described any more. Yen at 0 beside
kroner at 2 has no correct global value — 2 gives ¥1234.56, an amount yen
cannot represent; 0 rounds 49.95 DKK to 50 and drifts the carry from the bank.
Nothing in the app warns. docs/specs/2026-09-02-global-decimals-design.md
argues it in full, including what re-adding a per-currency override would take,
and AGENTS.md §1 now says not to reintroduce one without revisiting the
decision.
The 5 -> 6 step takes the MAXIMUM of the per-currency digits, not the base
currency's. A dataset holding a three-decimal currency already has
three-decimal amounts in it, and adopting the base's 2 would truncate the next
edit of one; the maximum can only keep more precision, never less. On every
dataset this app has written all four currencies record 2, so nothing rounds
differently than before.
Changing the setting does not rewrite stored amounts. 49.95 stays 49.95 and
shows as 50; totals recompute at the new precision. Rewriting each Money is a
destructive whole-dataset write, which §1 owes a backup export first, and it is
lossy one way.
Display turned out to be the hole in the plan. src/ui/format.ts pinned
minimumFractionDigits: 2 in a module-level Intl.NumberFormat, so it never read
the dataset at all — equally broken under per-currency digits, where a JPY
rendered "3,333.00", so a pre-existing gap rather than a regression. Shipping a
Settings control that display ignores would look broken at 0 and be lossy at 3,
hiding precision the dataset holds. So format.ts takes digits like roundMoney
does, useMoneyFormat() binds them for the 64 call sites, and postRowCells takes
the formatter as an argument because it is a plain helper, not a component.
currencyDigits.test.ts is rewritten rather than deleted. Driving a dataset at
ZERO decimals through rounding, both FX directions, both split modes, plan
division, the fold and the month view still tells a real implementation from
one assuming 2 — it just cannot prove per-currency flow, because there is none.
It also asserts that raising the setting to 2 changes what the fold produces.
Verified in Chrome, not only in tests: a v5 dataset with digits 2/0/3 written
straight into IndexedDB migrates to a setting of 3, the table loses its
Decimals column, and editing the control persists schema 6 with digits stripped
from each currency and income left at 20000.55. The same month reads 600/206 at
zero decimals and 600.000/205.561 at three, so the figures recompute rather
than merely reformat.
Not verified here: the .ods in a real spreadsheet.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
GBP joins the currencies the app comes with: £, two decimals, and a
committed fallback rate of 8.704735 DKK to the pound. build.ts now
fetches it too, so a build with a network bakes a live GBP rate and one
without still covers it — the coverage check derives from the seed table,
so it demanded GBP as soon as the table listed it.
The seed table alone would not have delivered this. Baked currencies and
rates seed a NEW dataset and nothing else, so an existing dataset would
have been left typing the code, name, symbol and decimals by hand. A
4 -> 5 migration adds sterling to a dataset that lacks it, with its rate.
Supplying a rate is the one thing the "rates never backstop a cleared
rate" rule permits here: it forbids re-supplying a number the owner
deleted, not introducing one for a currency they have never had. A GBP
the owner already defined, or a GBP rate they already hold, is left
exactly as it is — asserted, including the case where their definition is
"wrong" (zero decimals), because it is theirs.
This exposed a real latent bug. The 2 -> 3 step seeded the live
seed-currency table BY REFERENCE, so adding sterling there would have
retroactively changed what an old dataset received from a step it had
already been through — silently, and only for whoever had not migrated
yet. Every step now carries its own frozen copy, and a source-level guard
fails the build if a live default is imported again. Scoping that guard
took two goes: matching the whole file flagged the comment explaining the
rule, and then flagged the frozen local copy that is the fix.
Two test fixtures used GBP as their example of an UNSUPPORTED currency
and now use CHF, which no seed table lists.
Verified in a browser by writing a schemaVersion 4 dataset into IndexedDB
and reloading: the currency table gains "British pound / £ / 2" with
"manual · 2026-09-02", the post currency selector offers GBP, and the
income and post survive untouched. Note for the next person — a migration
applies in memory on load and is written back on the next mutation, so
reading IndexedDB straight after a reload still shows the OLD version.
That is recorded in docs/TODO.md, because it made this verification look
like a failure at first.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
"Fetch rates now" failed on the deployed site with nothing but a CORS
error. api.frankfurter.app now answers every request with a 301 to
api.frankfurter.dev/v1, and a redirect response must itself carry
Access-Control-Allow-Origin for a browser to follow it cross-origin. That
301 carries no CORS headers at all, so the request died before the
redirect could be taken.
Measured rather than guessed, with an Origin header set:
api.frankfurter.app -> 301, no access-control-* headers
api.frankfurter.dev -> 200, access-control-allow-origin: *
The response shape is unchanged, so parseFxResponse needed no edit.
Nothing was wrong at build time, which is why this went unnoticed: a
server-side fetch follows the 301 freely, so the baked rates were always
correct. Only the browser path was broken.
Two changes, because a new default alone fixes only some datasets:
- DEFAULT_FX_API_URL points at .dev/v1, with a test that fails if the
redirecting host ever comes back.
- A 3 -> 4 migration drops settings.fxApiUrl when it holds exactly the
dead default, which is the case for anyone who edited that field. It is
DROPPED rather than rewritten, so the dataset follows whatever the
current default is and the next move of the service needs no second
migration for the same user; a URL the owner chose is left strictly
alone. No stored figure changes, so it cannot alter a number in the
budget.
Verified by clicking the button in a real browser: "Updated 2 rate(s)",
USD 6.456195 and EUR 7.474959 both stored with source "api" — and the USD
figure differs from the baked constant, so it is a genuine live fetch.
Two migration tests asserted the chain ends at 3; they now assert
SCHEMA_VERSION, since what they mean is "all the way through".
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
AGENTS.md now holds the instructions and CLAUDE.md and GEMINI.md are
pointers to it. Three files of instructions become three files that
disagree; one file every agent reads cannot.
The content is reorganised rather than rewritten, into: the invariants,
the guards that fail the build, the validation this codebase deliberately
does not perform, the environment, and where to read next. Every guard
now names the test that catches it, and the two rules with no test behind
them are called out as such, because "only review catches this" is
information the reader needs.
Restructuring surfaced one rule that was missing here entirely — sw.js
must stay unhashed and be served no-cache — which had only ever been
written down in ARCHITECTURE.md.
Dropped: the `bun init` boilerplate code samples. Every rule they carried
is still stated; the hello-world test and the three frontend snippets are
not.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
ARCHITECTURE, PRODUCT and TODO move out of the repository root, and
docs/superpowers/{specs,plans} flattens to docs/{specs,plans}:
"superpowers" names the tool that wrote those documents, not a kind of
document.
No content changes. This commit is the move, plus the roughly thirty
cross-references the move invalidated.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Asked for as a reset that includes the currencies and the seed
categories. Between an empty dataset and first-run state the owner chose
first-run: the three starter posts, the DKK/USD/EUR table, the baked
rates, this month at zero income, no purchases.
store.reset() calls the same createSeedDataset(currentMonth, seedRates)
that load() uses on a first run, through the same write queue. Seeding
stays in the store rather than moving into the UI so "reset" and "a
brand-new browser" cannot drift apart, and a reset issued while a
mutation is still in flight cannot be overtaken by it.
The confirm panel reuses the import flow's shape and, more importantly,
its order of operations: the JSON backup downloads BEFORE the
destructive write, and a backup that fails aborts the reset rather than
destroying the only copy of the user's data. The write is guarded, which
src/ui/storeWriteErrors.test.ts requires of every direct store call in
the UI.
Also gives both confirm panels and the error line the top margin they
never had — they butted straight against the button row.
Verified by clicking through in real Chrome and reading IndexedDB back:
3 seed posts, DKK/USD/EUR, both baked manual rates, 0 purchases, one
month at zero income. Whether headless Chrome wrote the backup file is
not observable here, so the backup is issued rather than confirmed
openable — a gap the import flow has always had too.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Two requests. The second is small; the first changed the money layer.
TYPING THE CURRENCY. The purchase total field now reads "30$" as thirty
dollars, "€25,50" as EUR 25.50, "250 kr" as DKK, "1.234,56 usd" as USD
1234.56, and sets the currency selector from what was typed. Entry speed is a
stated product feature and a second control per amount works against it.
The field is type="text", not type="number": a number input silently discards
anything non-numeric, so "30$" would never reach the parser. It keeps its own
text so a half-typed "30." stays as typed and only commits when it parses.
Separator handling is where parseMoneyInput earns its 26 tests. With both "."
and "," present the LAST is the decimal point, which covers "1.234,56" and
"1,234.56" without knowing a locale. With one, it groups thousands if exactly
three digits follow and is a decimal point otherwise — so "1,500" is fifteen
hundred and "1,5" is one and a half. Spaces group thousands only in
three-digit groups, because "30 40" is two amounts typed by mistake and
committing it as 3040 would be worse than rejecting it. An unrecognised
currency returns null rather than falling back: reading "30 GBP" as 30 DKK
would book money at the wrong currency.
USER-DEFINED CURRENCIES. `Currency` was a closed union and decimal places were
a module constant, so "add a currency" was a code change. Both now live in the
dataset: `Dataset.currencies` is the authority on which codes are valid, what
they are called, their symbol, and how many decimals they round to. Settings
grows a table to add, edit and remove them.
That forced the money layer open. `roundMoney` takes a DIGIT COUNT, not a
currency code, and every one of its ~29 call sites resolves digits from the
dataset via `digitsFor`. Making digits a required number rather than an
optional one with a default of 2 is the whole safety argument: every site
became a compile error the type checker enumerated for me, where a default
would have left each one silently correct for DKK/USD/EUR and silently wrong
for the first zero-decimal currency the owner adds.
Because every existing currency uses two decimals, a broken version of this
refactor would still pass all 356 previous tests. src/domain/currencyDigits.test.ts
is the oracle that cannot lie: a JPY-style zero-decimal currency driven through
roundMoney, both FX directions, both split modes, finance-plan division, the
fold, and the month view, asserting no figure has a fractional yen in it.
Guards that come with it, all tested:
- Codes are identity — they key the FX table and every stored Money — so they
are normalised (" jpy " -> "JPY") and cannot be edited, only added/removed.
- A currency in use cannot be removed, and the refusal names what refers to
it. The same reasoning as posts being archived rather than deleted: stored
Money carries the code, and dangling references would make the import
validator refuse the owner's own exported file. Removing an unused one takes
its exchange rate with it, leaving no orphan row.
- The import validator now checks the currency table itself — codes, duplicate
codes, integer decimals 0-4 — and validates every Money against it. That
boundary check replaces the compile-time safety the closed union provided.
- parseFxResponse takes the accepted codes instead of a global constant, so a
rate service returning dozens cannot put unreachable rows in the table.
Migration v2 -> v3 seeds the currency table. Behaviour-preserving by
construction: every currency that existed had two decimal places and the
seeded table records two, so not one stored amount can round differently than
it did before. An existing `currencies` field is kept rather than overwritten,
since a hand-edited file could already carry currencies the owner added.
Verified in the browser, not just in tests: JPY added through the real Settings
form with 0 decimals, and the five inputs above typed into the real purchase
field, each setting the right currency.
Two obsolete test helpers went away. plans.test.ts and actions.test.ts used to
monkey-patch the CURRENCY_DIGITS constant to prove the table was consulted;
digits are an argument now, so those tests just ask for zero decimals.
types.test.ts no longer asserts "the supported currencies are exactly DKK,
USD, EUR" — that stopped being a property of the code.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
TODO section 2, designed and approved, now built. A brand-new dataset arrives
with DKK/USD/EUR rates instead of erroring on the first EUR purchase.
build.ts fetches at build time and embeds the result via `define`. A network
failure does NOT fail the build — it bakes committed constants instead, and an
incomplete response is treated as a failure too, since one unconvertible
currency is the problem this solves. Fetched rates carry source "api" and the
BUILD date, which is why parseFxResponse now takes an explicit updatedAt; the
constants carry source "manual" and their own date, so Settings never claims a
hardcoded number came from a rate service. SKIP_FX_FETCH=1 and FX_API_URL are
there for offline, CI and reproducible builds.
They seed a NEW dataset and nothing else. They are NOT a fallback for a missing
rate: clearing a rate removes its row so MissingRateError surfaces, rather than
silently converting money at a number the user never chose. A test asserts a
cleared rate still throws, and loading an existing dataset never touches its
rates.
Domain purity forced the shape. createSeedDataset takes the rates as an
argument (and copies the rows, so shared constants cannot be edited out from
under the caller); the env read lives in the new src/store/bakedRates.ts behind
the try/catch accessor, because an unset BUN_PUBLIC_* leaves a bare process.env
in the browser bundle; and createSnapshotStore takes seed rates as a parameter
so it stays free of the ambient environment, with src/store/index.ts wiring it.
Verified all three build paths: live fetch bakes api-sourced rates with today's
date, an unreachable endpoint and SKIP_FX_FETCH both bake manual constants and
still build, and the payload is present in the bundle in each case. Verified at
runtime that a fresh install converts EUR 100 -> 747.50 DKK and USD 100 ->
644.95 DKK with the variable both set and unset.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Each of these was recorded with its reasoning already settled; each is fixed
test-first, and two turned out to be worse than the note claimed.
EMPTY_FIGURES is frozen. figuresFor returns it by shared reference for every
(post, month) the fold has no entry for, so one consumer mutating its result
would have moved every other unknown row with it.
Split values now round by what they MEAN. A split's value is a percentage in
"percent" mode but MONEY in the purchase's currency in "fixed" mode; both were
rounded to a hardcoded 2 places. sliceTotal likewise rounded to DKK's minor
unit whatever currency the slices carried. Note this is narrower than TODO
claimed: round2 is still correct for Rule.percent, which is not money at all.
Neither bug is observable while every supported currency uses hundredths, so
the tests force CURRENCY_DIGITS for their duration.
confirmImport guards its write. A failed import was an unhandled rejection with
nothing shown; the dialog now reports it and keeps `pending` so the user can
retry. A source-level guard covers the whole UI, in the spirit of
eventCapture.test.ts.
The manifest has one definition. The dev placeholder did not merely hardcode
scope "/" — it was never served at all: the "/*" catch-all answered
/manifest.webmanifest with the HTML shell, as text/html, and /icon.svg too.
buildManifest moves to src/manifest.ts, the dev server generates both from the
base path, and the source file stays as a valueless resolution stub because
Bun.serve has no `external` option to skip the <link> href.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
setRuleFrom replaces rather than appends for a month that already has a
version, keeping the effective rule unambiguous, and keeps the series sorted.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Previously only an empty posts array was tested for the "no standingRule"
path; a post that IS present but lacks the field was exercised only by an
ad-hoc script, not a committed test. Asserts rules === [] (never a version
wrapping undefined, which would later crash resolveRule/ruleAt) and that a
sibling post's rule is unaffected.
A pure shape change: standingRule becomes one version effective from the fold
start, which is where it already applied from. Asserted behaviour-preserving —
every post in every month resolves to the same allocation before and after, so
no balance moves.
Post.standingRule becomes Post.rules: RuleVersion[], resolved by ruleAt() as
the last version effective at or before a month. Per-month overrides still win
outright; a post with no applicable version allocates zero rather than
applying its earliest rule backwards.
allocationFor keeps its signature, so the fold, the views and the ODS export
are untouched. Settings gets a read-only rule summary for now; the history
editor follows.
Fixes the three findings from the final whole-branch review:
- SnapshotStore.mutate/replace now serialize behind a promise queue, so
concurrent mutate() calls (e.g. two independent onChange handlers firing
before either write resolves) each clone from the previous commit instead
of racing on a stale snapshot and silently losing an edit. Preserves
write-before-move-snapshot, caller-visible rejections, structuredClone
identity, and non-wedging on a failed write. Adds tests for concurrent
mutations and a failing write mid-queue.
- DataSection's exportJson/exportOds are wrapped in try/catch and report
failures through the existing import error state/rendering, since a throw
(e.g. MissingRateError from buildOds) inside a plain onClick is invisible
to the error boundary. The pre-import JSON backup now explicitly aborts
the destructive replace if the backup export fails, rather than relying on
an uncaught throw to prevent it.
- PlanEditor no longer calls monthOf()/withPlan() with an empty or partial
date from a native <input type="date">, and requires an integer month
count (with step={1}) before calling withPlan/equalSlices, preventing
both domain throws from firing inside plain event handlers.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Rate fetching is optional and fails soft: any network or parse error
leaves cached rates untouched and shows a message, never throwing into
render. A cleared or non-positive FX rate input now calls the new
removeFxRate action instead of storing 0, since toBase() silently
converts a stored 0 to a 0-value conversion while an absent row
correctly throws MissingRateError. Posts are archived, never deleted.
Import downloads a backup of the current data before replacing it and
requires confirmation showing before/after counts.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Every mutation is a pure function over a draft dataset, so the write
surface is unit-tested without React. Money amounts (income, purchase
totals, split values, schedule slices, fixed/percent rule amounts) are
rounded to their currency's minor unit before they land in the draft,
per CLAUDE.md's round-before-persisting rule -- actions.ts is the
single boundary every UI mutation passes through. FxRate.baseUnitsPerOne
is deliberately exempt: it is stored at six decimal places, not money.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Persistence is injected, so the store is testable with no browser. Writes
land before the snapshot moves, so the UI never shows unsaved data.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
The dataset is one atomic record, so a write can never leave posts and
purchases inconsistent.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Lucas Winther