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.
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.
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.
Note that the autocomplete helper drives the server through
vscode-languageserver-protocol, cross-link the tooling decision, and replace
the obsolete string-id known issue with the benign context-canceled stderr
the Go server emits on shutdown.
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.
The autocomplete helper drives tsc --lsp --stdio; vscode-languageserver-protocol
supplies the transport (re-exported vscode-jsonrpc/node) and the typed LSP
requests, replacing the hand-rolled JSON-RPC client. Record the choice and
the rejected alternatives in tooling.md.
The autocomplete helper still carries a hand-rolled JSON-RPC client
(Content-Length framing, a pending-request map, server-request replies).
vscode-languageserver-protocol provides all of it plus typed requests, so
track the move as a task with subtasks.
No tests live under scripts/, and every test script (test, test:unit, test:ci,
watch:test) globs only src/**/*.test.ts, so state that. The scripts/**
oxlint scope it was confused with still exists and carries the same
import/no-nodejs-modules exception as the test-helper scope.
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 matcher is now two three-overload factories; library.md documents why
the union merge, inferred universe, conditional RequireKeys and cases-first
paths were rejected, and lists the two open issues (the fallback sees all of
T; a redundant _ is still accepted). testing.md records the language server
as the autocomplete oracle, and CONTRIBUTING points the exception at the
matcher's own test file.
The backlog marks the design-doc and autocomplete groundwork done alongside
the adoption.
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.
Agents may add the fixed file-level typescript/no-floating-promises
oxlint-disable header at the top of a `*.test.ts` file — the
expectTypeOf() misidentification is a documented false positive
(development/testing.md § Known issues) and the await/void workarounds
collide with eslint/no-void. Every other suppression stays the human
last resort it was.
development/testing.md § Test helpers: why name beats path under
import/no-relative-parent-imports, why the key needs `#`, why the
`__tests__` folder name, and what was rejected (flat placement, tsconfig
paths, rule exemptions).
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.
tmu