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.
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.
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 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`.
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`.
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.
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.
An open universe (`getMatcher<string>()`) types its handler map as an index
signature, so a runtime map with fewer keys still satisfies the exhaustive
overload. Calling the matcher with a missing shape reaches the dispatch guard
and throws — no cast needed.
When a fallback argument is present, the second overload supplies the
contextual type, so the handler map popup offers optional keys (`a? b? c?`)
and handled keys stay optional (`b? c?`). The exhaustive one-argument popup
is unchanged. Covered for both factories.
The factory-contract test now also covers a fallback whose return does not
fit the common return of the handler map — a `number` handler with a
`string` fallback — which `getMatcherW` accepts as `number | string`.
The fallback overload could not infer `R` from the handlers: `R` appeared
only inside the `Exact` constraint, which is not an inference site, so with
inferred handler params it collapsed to `unknown` and the matcher silently
returned `UnaryFn<T, unknown>`. Adding `Partial<Handlers<T, R>>` to the
handler parameter gives `R` an inference site, so the common return is
inferred from the handlers and the fallback alike.
Tests drop their explicit handler return annotations: real handlers are short
and unannotated, and the common type is now inferred from them.
The fallback is now the second factory argument — `(handlers, (s) => …)` —
so its parameter is `Exclude<T, keyof handlers>`. A property's contextual
type is fixed before TypeScript infers its sibling keys, so the remainder is
not expressible while the fallback sits in the handler map; a later argument
is contextually typed from inference on an earlier one.
Both factories take the new shape; the tests and autocomplete probes follow.
The generic overloads guard excess keys with type-fest's `Exact`, so the
error lands on the offending property. A redundant fallback (a full handler
map plus one) is still accepted — the guard for it does not survive inference
and is left to its backlog task.
The protocol cross-link and the TS-internal shutdown-race explanation were
too detailed for the category doc. The helper comment keeps a short,
self-contained note on the stdin-EOF workaround.
The completion helper is test-only (excluded from dist/), so the
style-only no-magic-numbers and unicorn/no-null warnings are tolerable
here. A file-level disable keeps them out of check:oxlint without touching
the project config.
The TS 7 Go server races Session.updateWatches against the exit
notification; handleExit returns io.EOF, the background context is
cancelled, and the bare error is flushed to stderr once the outgoing
queue closes (server.go / logger.go). Send shutdown and close stdin
instead: EOF makes the server exit cleanly (code 0, no output), with the
kill kept as a fallback. testing.md records the cause.
Replace the hand-rolled JSON-RPC client (framing, pending map, reply
dispatch) with createMessageConnection and typed requests from
vscode-languageserver-protocol. A catch-all onRequest answers the server
requests the old client replied to, and CompletionList/CompletionItem
replace the ad-hoc shape guards. Public LspSession API is unchanged.
Drop the strict/widened aliases from src/index.ts so the factories are
exported under their own names, and align the type tests, the autocomplete
probe (which now imports the public surface from ./index.ts) and library.md
with them.
Also correct the widened-overload comment: the excess-property check does not
apply to a generic P, so MatcherWidening's keyof guard — not the closed
constraint — is what rejects keys outside T/_, as library.md already
documented.
The helper's own contract — marker handling, requested position, label
extraction and the rejection when the marker is absent — is asserted against
in-memory documents whose contextual types are written inline, so the helper
is tested without coupling to the library's code.
strict/widened each take the exhaustive/fallback pattern shape in three
overloads ordered ExhaustiveLoose -> Fallback -> Handlers. TypeScript reads
the first overload for the object-literal popup (_?, a, b) and the last for
the missing-key error, so autocomplete and the error message are tuned
independently. The fallback is a pattern shape, not a factory, so the four
getPrimitiveUnionMatcher* factories collapse to two.
src/index.ts re-exports the two factories; the prototype scratch files that
explored the alternatives are removed.
src/util/__tests__/ holds shared test helpers, reached from anywhere
in the source tree as `#test-utils/<name>.ts` through
package.json#imports. A bare `~/…` is not a valid imports key — Node
requires `#` — and a direction-free specifier keeps
import/no-relative-parent-imports from ever firing. The `__tests__`
folder name is the pattern tsconfig.build.json already excludes, so
helpers can never ship. Lint scoping: import/no-nodejs-modules off for
the folder (the probe spawns a language server) and
typescript/promise-function-async off to match its promise-returning
style. The LSP probe moves in from scripts/; a smoke test pins the
specifier's resolution and typing without starting a server.
They were the template's demo API, not the library's real surface. Drop
them, their README walkthrough, and the tooling note that cited their
disable directives, and point index.ts at the primitive matchers that
remain.
The spec only exercised the template's match/P example API. Removing it
first lets the modules and exports it imports go next without leaving a
dangling reference.
Rewriting without any was evaluated; the alternatives were more
complex than the current solution. Record the rationale next to the
two oxlint-disable sites so the suppression is not re-litigated.
The primitive union matchers invoke every handler with the matched
literal, but the specs wrote their handlers with zero parameters, so
the passed value and its inferred key-literal type went untested.
Declare the parameter on each such handler and pin it with
expectTypeOf, matching the style the two already-correct handlers used.
The `_` fallbacks assert the whole union rather than a single literal.
Return-type expectations are unchanged, so the W / non-W widening
distinctions are still covered.
tmu