♻️ Name the matcher factories getMatcher / getMatcherW

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.
This commit is contained in:
tmu committed 2026-09-17 21:48:54 +00:00
1 parent 05fad0fcd6
commit 800c11139d
5 files changed
+69 -84

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+42 -42
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@@ -10,15 +10,15 @@ import {
LspSession,
} from "#test-utils/lsp-completion.ts";
import { strict, widened } from "./primitive.ts";
import { getMatcher, getMatcherW } from "./primitive.ts";
// ============================================================================
// API: strict — ✔️ Exhaustive / ✔️ ReturnsStrict
// API: getMatcher — ✔️ Exhaustive / ✔️ ReturnsStrict
// ============================================================================
test("strict: exhaustive pattern infers one common return type", () => {
test("getMatcher: exhaustive pattern infers one common return type", () => {
// Arrange
const factory = strict<"a" | "b">();
const factory = getMatcher<"a" | "b">();
// Act
const matcher = factory({
@@ -41,9 +41,9 @@ test("strict: exhaustive pattern infers one common return type", () => {
assert.equal(matcher("b"), 2);
});
test("strict: dispatches on numeric literal keys", () => {
test("getMatcher: dispatches on numeric literal keys", () => {
// Arrange
const factory = strict<1 | 2>();
const factory = getMatcher<1 | 2>();
// Act
const matcher = factory({
@@ -63,9 +63,9 @@ test("strict: dispatches on numeric literal keys", () => {
assert.equal(matcher(2), 20);
});
test("strict: dispatches on mixed string and numeric keys", () => {
test("getMatcher: dispatches on mixed string and numeric keys", () => {
// Arrange
const factory = strict<"a" | "b" | 1 | 2>();
const factory = getMatcher<"a" | "b" | 1 | 2>();
// Act
const matcher = factory({
@@ -96,12 +96,12 @@ test("strict: dispatches on mixed string and numeric keys", () => {
});
// ============================================================================
// API: strict — ❌ Exhaustive (fallback) / ✔️ ReturnsStrict
// API: getMatcher — ❌ Exhaustive (fallback) / ✔️ ReturnsStrict
// ============================================================================
test("strict: a `_` fallback makes the universe keys optional", () => {
test("getMatcher: a `_` fallback makes the universe keys optional", () => {
// Arrange
const factory = strict<"a" | "b" | "c">();
const factory = getMatcher<"a" | "b" | "c">();
// Act
const matcher = factory({
@@ -125,9 +125,9 @@ test("strict: a `_` fallback makes the universe keys optional", () => {
assert.equal(matcher("c"), 2);
});
test("strict: a `_` fallback also accepts an exhaustive pattern", () => {
test("getMatcher: a `_` fallback also accepts an exhaustive pattern", () => {
// Arrange
const factory = strict<"a" | "b">();
const factory = getMatcher<"a" | "b">();
// Act
const matcher = factory({
@@ -147,9 +147,9 @@ test("strict: a `_` fallback also accepts an exhaustive pattern", () => {
assert.equal(matcher("b"), "B");
});
test("strict: a `_` fallback routes mixed string and numeric gaps", () => {
test("getMatcher: a `_` fallback routes mixed string and numeric gaps", () => {
// Arrange
const factory = strict<"a" | "b" | 1 | 2>();
const factory = getMatcher<"a" | "b" | 1 | 2>();
// Act
const matcher = factory({
@@ -176,12 +176,12 @@ test("strict: a `_` fallback routes mixed string and numeric gaps", () => {
});
// ============================================================================
// API: widened — ✔️ Exhaustive / ❌ ReturnsStrict
// API: getMatcherW — ✔️ Exhaustive / ❌ ReturnsStrict
// ============================================================================
test("widened: exhaustive pattern widens to the union of handler returns", () => {
test("getMatcherW: exhaustive pattern widens to the union of handler returns", () => {
// Arrange
const factory = widened<"x" | "y">();
const factory = getMatcherW<"x" | "y">();
// Act
const matcher = factory({
@@ -204,9 +204,9 @@ test("widened: exhaustive pattern widens to the union of handler returns", () =>
assert.equal(matcher("y"), "two");
});
test("widened: dispatches on mixed string and numeric keys", () => {
test("getMatcherW: dispatches on mixed string and numeric keys", () => {
// Arrange
const factory = widened<"a" | "b" | 1 | 2>();
const factory = getMatcherW<"a" | "b" | 1 | 2>();
// Act
const matcher = factory({
@@ -239,12 +239,12 @@ test("widened: dispatches on mixed string and numeric keys", () => {
});
// ============================================================================
// API: widened — ❌ Exhaustive (fallback) / ❌ ReturnsStrict
// API: getMatcherW — ❌ Exhaustive (fallback) / ❌ ReturnsStrict
// ============================================================================
test("widened: a `_` fallback widens gaps into the union", () => {
test("getMatcherW: a `_` fallback widens gaps into the union", () => {
// Arrange
const factory = widened<"x" | "y" | "z">();
const factory = getMatcherW<"x" | "y" | "z">();
// Act
const matcher = factory({
@@ -270,9 +270,9 @@ test("widened: a `_` fallback widens gaps into the union", () => {
assert.equal(matcher("z"), "fallback");
});
test("widened: a `_` fallback widens mixed string and numeric returns", () => {
test("getMatcherW: a `_` fallback widens mixed string and numeric returns", () => {
// Arrange
const factory = widened<"a" | "b" | 1 | 2>();
const factory = getMatcherW<"a" | "b" | 1 | 2>();
// Act
const matcher = factory({
@@ -301,9 +301,9 @@ test("widened: a `_` fallback widens mixed string and numeric returns", () => {
assert.equal(matcher(2), "fallback");
});
test("widened: a `_` fallback also accepts an exhaustive pattern", () => {
test("getMatcherW: a `_` fallback also accepts an exhaustive pattern", () => {
// Arrange
const factory = widened<"x" | "y">();
const factory = getMatcherW<"x" | "y">();
// Act
const matcher = factory({
@@ -327,9 +327,9 @@ test("widened: a `_` fallback also accepts an exhaustive pattern", () => {
// Factory contracts — calls that must not compile
// ============================================================================
test("strict factory rejects patterns outside its contract", () => {
test("getMatcher factory rejects patterns outside its contract", () => {
// Arrange
const factory = strict<"a" | "b">();
const factory = getMatcher<"a" | "b">();
// Act / Assert — the calls below must not compile.
// `Parameters<typeof factory>[0]` resolves only the *last* overload, so it
@@ -345,9 +345,9 @@ test("strict factory rejects patterns outside its contract", () => {
factory({ a: () => 1 });
});
test("widened factory rejects patterns outside its contract", () => {
test("getMatcherW factory rejects patterns outside its contract", () => {
// Arrange
const factory = widened<"x" | "y">();
const factory = getMatcherW<"x" | "y">();
// Act / Assert — the calls below must not compile
// @ts-expect-error `z` is not part of the universe `"x" | "y"`
@@ -376,14 +376,14 @@ const UNIVERSE = `"a" | "b" | "c"`;
// documents, project membership), so they pass in any order.
const labelsFor = (
name: string,
factory: "strict" | "widened",
factory: "getMatcher" | "getMatcherW",
body: string,
): Promise<readonly string[]> => {
const session = new LspSession(REPO_ROOT);
const target: CompletionTarget = {
file: `src/__autocomplete_${name}.ts`,
source: [
`import { ${factory} } from "./primitive.ts";`,
`import { ${factory} } from "./index.ts";`,
`const m = ${factory}<${UNIVERSE}>()({`,
body,
"});",
@@ -398,10 +398,10 @@ const labelsFor = (
test("autocomplete: an exhaustive pattern requires the universe, `_` optional", () => {
// Arrange
const name = "strict_fresh";
const name = "getMatcher_fresh";
// Act
const labels = labelsFor(name, "strict", " /*COMPLETE*/");
const labels = labelsFor(name, "getMatcher", " /*COMPLETE*/");
// Assert
return labels.then((result) => {
@@ -411,12 +411,12 @@ test("autocomplete: an exhaustive pattern requires the universe, `_` optional",
test("autocomplete: handled keys drop out of the popup", () => {
// Arrange
const name = "strict_after_key";
const name = "getMatcher_after_key";
// Act
const labels = labelsFor(
name,
"strict",
"getMatcher",
" a: () => 1,\n /*COMPLETE*/",
);
@@ -428,12 +428,12 @@ test("autocomplete: handled keys drop out of the popup", () => {
test("autocomplete: `_` makes the remaining keys optional", () => {
// Arrange
const name = "strict_after_fallback";
const name = "getMatcher_after_fallback";
// Act
const labels = labelsFor(
name,
"strict",
"getMatcher",
" _: () => 0,\n /*COMPLETE*/",
);
@@ -443,12 +443,12 @@ test("autocomplete: `_` makes the remaining keys optional", () => {
});
});
test("autocomplete: `widened` offers the same popup as `strict`", () => {
test("autocomplete: `getMatcherW` offers the same popup as `getMatcher`", () => {
// Arrange
const name = "widened_fresh";
const name = "getMatcherW_fresh";
// Act
const labels = labelsFor(name, "widened", " /*COMPLETE*/");
const labels = labelsFor(name, "getMatcherW", " /*COMPLETE*/");
// Assert
return labels.then((result) => {