The README collapsed to API-only prose once the old match/P surface was
dropped. Rebuild its entry-point shape: a quick-start Synopsis walked through
a Contact union, a dedicated Installation section, and a real-world Examples
section (primitive-union dispatch, a fallback, a property union narrowed by
the tagged-union matcher, and the widening variant).
Set the tagline and Description to the library's identity — exhaustive,
type-safe pattern matching for TypeScript — and state the goal Moose-style:
type-safe pattern matching with a lean syntax, accomplished by exhaustive
branches and typed per-branch handler parameters, backed by autocomplete and
a tiny footprint. Drop the F#-style framing and the stale "matches method is
a type guard" and "(not regex)" copy from the README, AGENTS.md and the
package.json description. Every fence is a doc-test, so the examples cannot
drift from the API.
The builder types are already the inferred return types and travel into
the emitted .d.ts, so exporting them only made them nameable while
pinning the internal Strict/Widening split as API. Revert the type
exports and the public renames, drop the type-surface test, and document
only the factories in README and development/library.md.
Export the matcher builder types from the barrel and rename them off the
internal Strict/Widening suffixes, so the type a factory returns is
nameable: PrimitiveUnionMatcher/W, TaggedUnionMatcher/W, and the
tagged-union factory types. Add TSDoc to every public symbol — the
declarations carry it into the published package — and pin the exported
names in src/index.test.ts.
Document the API in README and record the surface decision (and the
rejected matcher-shared export) in development/library.md.
test:ci now runs c8 with --all --include "src/**/*.ts" --100, so the
build job fails when any runtime file under src/ is untested. --all is
what makes the gate non-vacuous: without it c8 counts only the files the
suite happened to load, and a new untested module stays invisible.
Add src/index.test.ts to load the public barrel, which was previously
never imported at runtime and so read as 0% under --all. matcher-shared.ts
is types-only (an empty runtime image) and carries a file-level c8 ignore
with the reason.
Why 100% and the rejected alternatives: development/ci.md § Coverage
threshold.
`UnsupportedReason` tested `IsLiteral<PatternKey<T>> extends false`.
`IsLiteral` is `boolean` for a union that mixes a literal with a broad
type (`"a" | \`x-${number}\``), so `boolean extends false` is false and
the mix was accepted. Test `extends true` instead, which rejects it.
Found while adding property-union broad-universe coverage; the gate is
shared with the primitive-union matcher.
The tagged-union matcher selected handler parameters with
`Extract<T, Record<K, V>>`, which only keeps a member whose
discriminant is a singleton literal. A property that is itself a
union (`{ color: "red" | "green" | "blue" }`) or optional
(`{ type?: "x" }`) matched no member, so every handler received
`never`, and the fallback saw the whole shape instead of the
unhandled tags.
Replace the selector with `Narrowed`, which distributes over `T`,
drops a member whose `K` cannot take the tag, and narrows `K`. The
`T[K] extends V` fast path keeps an exact member (a discriminated
union's declared interface) untouched. The fallback reuses
`Narrowed` over `Exclude<Tags, HandledTags>`, so a union-valued
property narrows to the unhandled tags rather than the whole shape.
Matching a defined tag on an optional property makes the key
required (`{ type: "x" }`); the `undefined` tag yields
`{ type?: never }` under `exactOptionalPropertyTypes` (absence) or
`{ type?: undefined }` when the property admits an explicit
`undefined`.
Remove every done/cancelled backlog item; the reasons they recorded are
already in development/ (library.md, testing.md, tooling.md, workflow.md)
and git history is the archive.
The one exception was the TS 7 LSP shutdown workaround, which lived only in
a code comment. Record it under development/testing.md § Autocomplete
(Known issue) before dropping the bug item.
Bump every direct dependency to the latest registry version: cspell
10.3.3, knip 6.38.0, oxfmt 0.70.0, oxlint 1.85.0, oxlint-tsgolint
7.0.2002 and type-fest 5.10.0, plus their transitive updates. oxfmt is
the only range widened (^0.68.0 -> ^0.70.0); the rest moved within
their existing semver ranges.
`npm run maintain:outdated` is now clean and `npm run verify` is green
with no rule or format fallout. `maintain:knip` still reports the
pre-existing `src/index.ts` false positive (dist-only `exports`), which
predates this bump.
`getMatcher` / `getMatcherW` become `getPrimitiveUnionMatcher` /
`getPrimitiveUnionMatcherW`; `src/primitive.ts` and its test move to
`src/primitive-union.*`. The `Union` suffix mirrors `getTaggedUnionMatcher`.
Extend the matcher universe beyond string | number so a union can carry
boolean, null and undefined members. true|false, null and undefined are
not property keys, so handler keys are their stringification while the
callback still receives the real member. Symbols are rejected (a brand
is compile-time only) and bigint is not a property key.
A fallback paired with a handler map that already covers `T` was still
accepted, even though its remainder is empty. Fold the guard into
`Handled`'s own (F-bounded) constraint so it is checked after inference;
a conditional in the fallback parameter is evaluated while `Handled` is
still its constraint and rejects every partial map whose handler callbacks
need contextual typing.
Drop the leaf-task exception in AGENTS.md: a task without subtasks was implemented on the current branch, bypassing create:branch / create:finish. Every task now opens and closes a branch, so the clean-tree / current-main / green-baseline preconditions and the post-merge verify always apply.
Rewrite development/library.md around the new shape: the fallback is a second
argument (so it can receive the remainder), `R` needs an inference site in the
handler map, `Exact` restores the excess-property check, and the overload order
is load-bearing. Record this branch's rejected alternatives (single-object `_`,
currying, `this`/HKT, variance/`const`/`NoInfer`/brands) and the redundant-
fallback known issue. Add the changelog note and check off the backlog task.
Actionable sentence in CONTRIBUTING.md § Rules the tools don't enforce;
the why — humans skim, agents imitate the dominant style, so verbosity
compounds — in development/README.md § Decision blocks. Both sides in
one commit per the write-each-fact-once rule.
DefinitelyTyped keeps the @types/node latest dist-tag on the LTS line,
so check-outdated compared the current-line types against a lower
version: a permanent "reverted" flag, scan exit 1, zero signal. Ignored
by package name; --types filtering and a version-scoped pin rejected
(rationale in development/tooling.md).
@types/node to ^26.6.1 and cspell to ^10.3.2 — the only packages
check-outdated found behind the registry, both bumps within the existing
semver ranges. cspell 10.3.2 drops its transitive
fast-json-stable-stringify. npm run verify is green with no rule or
format fallout. maintain:outdated still flags @types/node as "reverted"
because DefinitelyTyped's latest dist-tag stays on the 22.x LTS series;
known false positive, advisory scan only.
`create:finish` leaves the merge local until `create:release` pushes it, so
`main` is routinely ahead of its upstream between a merge and a release. The
branch front door demanded an exact match and refused until it was pushed,
forcing a manual `git push` that the model deliberately keeps out of it.
Reject only a `main` that is behind its upstream — matching `create:finish`,
which already tolerates being ahead — and record why pushing from `finish` was
rejected instead. The push stays with `create:release`, so the merge remains
reviewable locally, and the known issue about the deadlock is gone.
Resolves: backlog task "Resolve the finish/push tension".
A merged branch must carry a final commit adding a short summary of the
work under [Unreleased] in CHANGELOG.md. create:release derives the bump
heuristic from that body, so notes have to exist before release day;
rationale in development/workflow.md.
Release front-door: pubv runs preflight + the interactive semver
heuristic and graduates CHANGELOG.md [Unreleased] -> dated; npm version
syncs package.json + lockfile; git commit --amend folds them into
pubv's single release commit; the tag is created AFTER the amend so it
marks the exact commit on main that gets published; then push. Tags are
v-less (--tag-prefix=none) to match the changelog compare refs.
@runwisp/pubv added as a devDependency. The short "how we got here /
what was rejected" note lives as a comment atop the script; the docs/
exploration was removed as too much to read.
tmu