The backlog item asked for a 5.0 baseline; the floor is 5.9 (set by type-fest
and the library's own gate), so the text now says "the TypeScript floor".
The exact-equality `toEqualTypeOf` assertions already reject `any`, so the
`.not.toBeAny()` guards were redundant. Refresh the fixture header and
development/ci.md to match.
The pipeline bullet's "(push to `main` / tag)" read like a local push hook.
State plainly that `compat` has no local tier — it is not in `check`, `verify`,
`test:ci` or any hook — and is run manually with `build && test:compat`.
Give the primitive-union handlers a parameter and assert its member type, and
assert the tagged-union widening handler's parameter too. A matcher without
handler-parameter assertions cannot catch a wrong or `any` handler parameter:
the matcher's own `(shape: T) => R` type is built from `T` and the handler
return, so it stays correct even when `Member<T, K>` inversion is broken.
Add a `compat` job that type-checks the whole suite and a consumer fixture
against the minimum supported TypeScript (5.9), reusing the `dist/` artifact
`build` produced and gating `publish`. The compiler is resolved by npx, so it
never enters `devDependencies` or the local `check`/`verify` loop.
The fixture imports the package by name, resolving the emitted declarations
through the `exports` map; `expectTypeOf` / `.not.toBeAny()` make it reject an
`any`-typed declaration, which a bare compile would accept.
Correct the README consumer floor from >= 5.0 to >= 5.9 (set by `type-fest`)
and drop the `node10` resolution claim, which the exports-only entry never
satisfied.
The agent-side LSP extension is declared in `.pi/settings.json`, not in
`package.json`, so neither `npm update` nor `maintain:outdated` sees it.
Bump it with `pi install npm:@spences10/pi-lsp@0.0.47 -l`, which
rewrites the pin and refreshes the gitignored `.pi/npm/` install cache,
then reformat the file: pi writes it back in its own two-space style,
which `check:oxfmt` rejects.
0.0.47 bounds the project-binary trust prompt — it follows tool
cancellation and times out after 30 s, returning a tool error instead of
leaving the session stuck in `Working`, and an allow-once decision now
survives an idle language-server restart. The read-only usage and the
`tsc --lsp` wiring are unchanged, so `development/tooling.md` only moves
the recorded version. No changelog note: the pin is agent tooling, not
shipped code, as when it was adopted (863198d).
The running pi session still has 0.0.46 loaded; restart pi to pick up
the new version.
knip derives the public entry from package.json `exports` and resolves
it to src/index.ts itself, so naming the file in `entry` is redundant:
maintain:knip reported it as a configuration hint, and the scan is now
silent. Verified the barrel is still treated as the entry — the scope
is clean with and without dist/, and with src/index.test.ts removed.
Supersedes the workaround recorded in development/tooling.md, which
silenced an unused-file report for the barrel that the current entry
derivation no longer produces. Rewrite the section to state the
behaviour and keep the rejected `paths` mapping.
Bump every direct dependency to the latest registry version: cspell
10.3.5, oxfmt 0.71.0, oxlint 1.86.0, oxlint-tsgolint 7.0.2003,
@types/node 26.6.3, the LSP protocol types 3.18.4 and 85 transitive
entries. oxfmt is the only range widened (^0.70.0 -> ^0.71.0), because
0.x minors are breaking under semver and `npm update` stops at the
range; the rest moved within their existing ranges.
`npm run maintain:outdated` is clean and `npm run verify` is green with
no rule or format fallout. `maintain:knip` reports one configuration
hint — the redundant `src/index.ts` entry pattern in knip.json — but
knip did not move, so the hint predates this bump and stays advisory.
Remove every done/cancelled item. Git history is the archive and each
item's rationale already lives in the README, in development/ or in a
released changelog entry; none was recorded only here, so no item had to
be rescued into development/ before it could go.
- drop the `v1.0:` and `Matcher:` projects too: their last open task is
done, so those headers would stand empty
- summarise the change under `[Unreleased]` in the changelog
Add a short README section under Alternatives, one heading per
alternative (ts-pattern, Effect.Match, match-iz and plain switch), each
saying what it is and what tiny-pattern-ts is or does differently. State
the data-last, pipe-friendly shape in Description.
- measure the footprint: ~0.2 kB minified + gzipped, not the
unminified ~1.8 kB; ts-pattern is ~2 kB
- correct match-iz: it ships types, it just cannot prove exhaustiveness
- drop switchcase / ts-match (unmaintained)
- check off the backlog task
Resolves: backlog "Add comparison section vs. other TS pattern-matching libs"
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.
Drop the `pretest:ci` lifecycle hook and call `create:doc-tests` from the
`build` job before `test:ci`. The hook hid the step from the job log and
made `test:ci` behave differently under npm than when run directly.
An example that exercises a line no hand-written test reaches would let
the `--100` gate pass on documentation alone. Node has no file-level
exclusion, and c8's `--exclude` only filters the report, so run the two
in separate processes: `test:coverage` runs c8 over the tracked tests
only (`git ls-files`, which skips the untracked generated files), and
`test:doc` runs the generated examples without c8. `test:ci` chains
them.
`assert` is the sole injected exception: the generated test always binds
it, so a fence must not import it. Revert the README imports and the
generator's node:assert merging; the fences keep the assigned variables
and `assert.equal` calls, and the generator again rejects a fence that
imports node:assert.
Assign every documented matcher result to a variable and assert it with
`assert.equal`, so the compiled README doc-tests verify behavior instead
of merely running the code. The examples import `node:assert` themselves
to stay copy-pasteable; the generator now merges that import into its
prelude assert rather than rejecting it (only `node:test` remains
reserved).
Every `ts`-tagged fence in README.md / CONTRIBUTING.md now becomes an
executed `node:test` case in a gitignored generated file, so a
documented example cannot drift from the API. The generator hoists and
merges the leading imports, rewrites the library specifier to the
`#test-tiny-pattern-ts` alias, and rejects a fence with no describing
paragraph or one that re-imports a prelude module.
CI regenerates via `pretest:ci`; `create:doc-tests` runs the generator,
formats, then typechecks the output against a scoped tsconfig that
relaxes `noUnusedLocals`. c8's default excludes already omit the
generated `*.test.ts`, so `test:ci` is unchanged.
Bump the copyright to 2026 in LICENSE and README, add the
comparison-section notes to the backlog, and trim the primitive-union
factory JSDoc now that the universe rules live in README § Caveats.
Each README and JSDoc example now assigns the function that takes the
handler object (the factory result, or the tagged key step) to a match…
variable and reuses it, so the builder is created once instead of per
call.
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.
State that the `W` suffix means widening and what that widens: the
matcher's return value goes from one common `R` to the union of every
handler's return type.
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.
Add a README Caveats subsection with user-facing guidance for the two
open-universe shapes: parse external input at the boundary down to a
finite union, or use a runtime Map registry for extensible domains.
Point the finite-universe bullet at it, and point the rejected
fix/open-universe-* entry in development/library.md back at the new
guidance, so rule and decision cross-reference without duplicating each
other.
Add property-union tests for the completion popup, a broad value in the
union, and value/stringification collisions. Rename the existing
property-union tests to a `property union:` prefix so they can be
selected with `--test-name-pattern`, and extend the autocomplete helper
with a `key` option so a probe can complete on a property other than
`kind`.
`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.
Listing scripts/*.ts in knip's `entry` replaced its default entry
detection, which derives the public entry from package.json `exports`.
Adding the CLI scripts therefore dropped the library entry, so knip
resolved the package through dist/index.js and flagged the unreferenced
src/index.ts as unused. Name the source entry alongside the scripts.
Record the rationale in development/tooling.md.
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.
Record why open universes and value/stringification collisions are
rejected, the `Member<T, K>` inversion, and the findings from the
rejected open-universe attempt so they are not re-run.
An open universe (`string`, `number`, a template literal) makes the
handler map index-like, so a partial object satisfied the exhaustive
overload and the runtime `dispatch` throw was reachable. A universe
containing a member and its stringification (`"true" | true`, `1 | "1"`)
collapsed two members onto one key.
- reject broad universes and value/stringification collisions at the
factory, with a diagnostic naming the reason
- invert `PatternKey` against the universe (`Member<T, K>`) instead of
`PatternParam<K>`, so a standalone `"true"` is typed `"true"`
- intersect `UniverseGate<T>` into the handler and fallback parameters,
preserving `R` inference and the popup
Rename `MatcherStrict` / `MatcherWidening` to
`PrimitiveUnionMatcherStrict` / `PrimitiveUnionMatcherWidening`, matching
the exported `getPrimitiveUnionMatcher(W)` names and the
`TaggedUnionMatcher*` pair.
Folds in the working-tree lint cleanups: drop the now-unneeded
`typescript/unified-signatures` disables and turn the tagged-union
factory interfaces into type aliases.
A `boolean` / `null` / `undefined` discriminant cannot key a handler
map, so the tagged-union matcher now routes it through the
`PatternKey` / `PatternParam` projection the primitive-union matcher
already used. Both matchers share the projection from
`matcher-shared.ts`; `MapTaggedUnion`, `Handlers`, `HandledMembers`
and `MustBePartial` key off the projected form and invert it to
recover the real member.
Covers exhaustive and fallback dispatch, the redundant-fallback
guard, and the LSP popup offering the tags by name.
`getMatcher` / `getMatcherW` become `getPrimitiveUnionMatcher` /
`getPrimitiveUnionMatcherW`; `src/primitive.ts` and its test move to
`src/primitive-union.*`. The `Union` suffix mirrors `getTaggedUnionMatcher`.
Record the non-exhaustive broad-type hole in the primitive matcher and the
never-typed handler parameters the tagged-union matcher produces when a
property is a union, so both can be picked up as their own work units.
A handler's `expectTypeOf(shape)` only proved the type the compiler inferred;
nothing observed the argument `dispatch` passed. Passing `String(shape)` at the
call site therefore kept the whole suite green while breaking every key whose
property name differs from its value (`true`, `null`, `1`).
Pair each handler expectation with a runtime assertion: `assert.equal` where a
handler runs for one shape, the disjunction over the set a `_` fallback accepts
where it runs for several. Where the exact value matters the fallback returns
its shape verbatim and the call site asserts it; a widening pattern absorbs the
remainder type into the return union, so the claim stays strict-free. The
mutation above now fails 10 of the 33 tests.
Rule: CONTRIBUTING.md, rationale: development/testing.md § Handler arguments.
String(shape) defeats V8's numeric-key fast path (measured ~2x on
number-keyed dispatch). JS already coerces boolean/null/undefined to the
same property key, so assert shape to string | number and index directly.
The assertion is TS2538-only; the facade keeps it sound. Needs a source
no-unsafe-type-assertion disable, next to the existing one.
State the end-user limits once, in README § Caveats: a member colliding
with its stringification, the unsupported symbol/bigint, and NaN/-0. Drop
the duplicated known-issue prose from development/library.md and the
source comment; link to the README instead.
Drop the fixed no-floating-promises header exception from CONTRIBUTING.md
and AGENTS.md; agents must not add a source disable or edit .oxlintrc.json.
Record the split in tooling.md and testing.md: a one-site false positive is a
source disable, a file-class one lives in the test override.
The no-floating-promises header was repeated at the top of every test
file. Centralize it, and the no-null suppression the new null/undefined
cases need, in the **/*.test.ts override.
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.
tmu