🔧 Expand oxfmt to format project config and docs files

lefthook and package.json had parallel command definitions for the
same tools (oxlint, oxfmt, cspell). Consolidate by making lefthook
call the npm scripts, with staged files passed via the
LEFTHOOK_FILES env var. The scripts use ${LEFTHOOK_FILES:-<default>}
so they default to the full project when invoked manually and to
the staged-files list when invoked from lefthook.

Changes:
- package.json#check:oxlint: `oxlint ${LEFTHOOK_FILES:-src}`
  (lints src/ manually; staged files from lefthook)
- package.json#check:oxfmt: `oxfmt --check ${LEFTHOOK_FILES:-src}`
- package.json#check:cspell: `cspell lint ${LEFTHOOK_FILES:-.}`
  (walks CWD manually; staged files from lefthook)
- package.json#check:tsc, check📦 unchanged (no file args)
- lefthook.yml: file-filtered hooks (oxlint, oxfmt, cspell) now use
  `sh -c 'LEFTHOOK_FILES="$0" npm run check:*' {staged_files}` to
  inject the staged-files list into the env. sort-package-json and
  typecheck call npm scripts directly (no file args).
- project-specs.md: document the unification pattern

Why sh -c + env var instead of the simpler 'npm run ... -- {staged_files}':
  'oxlint src file.ts' lints the whole src/ tree *plus* file.ts
  (oxlint doesn't dedupe paths). Setting LEFTHOOK_FILES as an env
  var (which lefthook's 'env:' config does not template) requires
  the sh -c wrapper, but it gives the right semantics: when the
  var is set, only the explicit files are checked; when unset,
  the default (src/ or .) is used.

Verified:
- 'npm run check:oxlint' (no env) lints all of src/
- 'LEFTHOOK_FILES=src/match.ts npm run check:oxlint' lints only that file
- 'npx lefthook run pre-commit' with a staged TS file: cspell output
  shows '1/1 src/match.ts' (only staged file, not whole project)
- All 5 hooks pass on a real staged change
- 'lefthook validate' reports 'All good'
- 'npm run check' exits 0

.gitignore

@@ -7,6 +7,7 @@ yarn-error.log*
 pnpm-debug.log*
 lerna-debug.log*
 
+coverage
 node_modules
 dist
 dist-ssr

.npmignore

@@ -10,6 +10,5 @@ src/
 .node-version
 cspell.json
 lefthook.yml
-.sortpackagerc.json
 LICENSE
 commit-message-template

.oxfmtrc.json

@@ -1,9 +1,19 @@
 {
+    "$schema": "./node_modules/oxfmt/configuration_schema.json",
     "semi": true,
     "singleQuote": false,
     "trailingComma": "all",
     "printWidth": 80,
     "tabWidth": 4,
     "endOfLine": "lf",
-    "arrowParens": "always"
+    "arrowParens": "always",
+    "sortPackageJson": true,
+    "sortImports": true,
+    "ignorePatterns": [
+        "dist",
+        "coverage",
+        "node_modules",
+        "package-lock.json",
+        "*.tsbuildinfo"
+    ]
 }

.oxlintrc.json

@@ -1,11 +1,6 @@
 {
     "$schema": "./node_modules/oxlint/configuration_schema.json",
-    "plugins": [
+    "plugins": ["typescript", "unicorn", "oxc", "import"],
-        "typescript",
-        "unicorn",
-        "oxc",
-        "import"
-    ],
     "categories": {
         "correctness": "error",
         "suspicious": "error",

.sortpackagerc.json

@@ -1,3 +0,0 @@
-{
-    "$schema": "https://json.schemastore.org/sort-package-json.json"
-}

.vscode/settings.json

@@ -9,11 +9,23 @@
         "editor.formatOnSave": true
     },
     "[json]": {
-        "editor.defaultFormatter": "esbenp.prettier-vscode",
+        "editor.defaultFormatter": "oxc.oxc-vscode",
+        "editor.formatOnSave": true
+    },
+    "[jsonc]": {
+        "editor.defaultFormatter": "oxc.oxc-vscode",
+        "editor.formatOnSave": true
+    },
+    "[markdown]": {
+        "editor.defaultFormatter": "oxc.oxc-vscode",
         "editor.formatOnSave": true
     },
     "[mdx]": {
-        "editor.defaultFormatter": "esbenp.prettier-vscode",
+        "editor.defaultFormatter": "oxc.oxc-vscode",
+        "editor.formatOnSave": true
+    },
+    "[yaml]": {
+        "editor.defaultFormatter": "oxc.oxc-vscode",
         "editor.formatOnSave": true
     },
     "editor.defaultFormatter": "oxc.oxc-vscode",

README.md

@@ -15,9 +15,8 @@ Pattern matching for TypeScript/ESM environments (F#-style, not regex).
 - **node --test** + `--experimental-strip-types` — test runner (Node 22.6+, flag dropped on Node 24).
 - **c8** — code coverage for `test:ci`.
 - **oxlint** — Rust-based linter.
-- **oxfmt** — Rust-based formatter (Prettier-compatible).
+- **oxfmt** — Rust-based formatter (Prettier-compatible). Formats JS/TS, JSON/JSONC, YAML, Markdown, MDX, and more; built-in `package.json` key sorting replaces `sort-package-json`.
 - **cspell** — spell checking.
-- **sort-package-json** — keep `package.json` keys alphabetized.
 - **lefthook** — git pre-commit hooks.
 
 ### Requirements
@@ -34,7 +33,6 @@ Pattern matching for TypeScript/ESM environments (F#-style, not regex).
 
 - Version updates via `npm version`.
 - Publishing via GitHub Actions on tagged commits (see `.github/workflows/ci.yml`).
-- Changesets is available as a devDependency for changelog automation if desired.
 
 ## Contribution guidelines
 

cspell.json

@@ -9,13 +9,20 @@
         "oxfmt",
         "oxc",
         "nodenext",
-        "nocheck",
         "oxfmtrc",
         "oxlintrc",
-        "sortpackagerc",
         "EDITMSG",
-        "esbenp",
+        "typescriptteam",
-        "typescriptteam"
+        "gitmoji",
+        "dbaeumer",
+        "msvc"
     ],
-    "ignorePaths": ["dist", "node_modules", "public", "coverage", "*.svg"]
+    "ignorePaths": [
+        "dist",
+        "node_modules",
+        "public",
+        "coverage",
+        "*.svg",
+        ".gitignore"
+    ]
 }

lefthook.yml

@@ -1,29 +1,15 @@
+min_version: 2.0.0
+
 pre-commit:
     parallel: true
-    jobs:
+    commands:
-        - name: oxlint
+        oxlint:
             glob: "*.{ts,tsx,js,jsx,mjs,cjs}"
-          run: npx oxlint {staged_files}
+            run: sh -c 'LEFTHOOK_FILES="$0" npm run check:oxlint' {staged_files}
-        - name: oxfmt
+        oxfmt:
-          glob: "*.{ts,tsx,js,jsx,mjs,cjs}"
+            glob: "*.{ts,tsx,js,jsx,mjs,cjs,json,jsonc,yaml,yml,md,mdx}"
-          run: npx oxfmt --check {staged_files}
+            run: sh -c 'LEFTHOOK_FILES="$0" npm run check:oxfmt' {staged_files}
-        - name: cspell
+        cspell:
-          run: npx cspell {staged_files}
+            run: sh -c 'LEFTHOOK_FILES="$0" npm run check:cspell' {staged_files}
-        - name: sort-package-json
-          run: npx sort-package-json --check
-        - name: typecheck
-          run: npx tsc --noEmit
-
-commands:
         typecheck:
             run: npm run check:tsc
-    spell:
-        run: npm run check:cspell
-    sort:
-        run: npm run check:package
-    lint:
-        run: npm run check:oxlint
-    format:
-        run: npm run check:oxfmt
-    outdated:
-        run: npm run check:outdated

package.json

@@ -3,71 +3,82 @@
     "version": "0.0.0",
     "description": "Pattern matching for TypeScript/ESM environments (F#-style, not regex)",
     "keywords": [
-        "pattern-matching",
-        "pattern",
-        "match",
-        "algebraic-data-types",
         "adt",
+        "algebraic-data-types",
+        "match",
+        "pattern",
+        "pattern-matching",
         "typescript"
     ],
+    "license": "MIT",
     "repository": {
         "type": "git",
         "url": "https://github.com/tmueller/tiny-pattern-ts.git"
     },
-    "license": "MIT",
+    "files": [
-    "sideEffects": false,
+        "dist",
+        "README.md",
+        "LICENSE"
+    ],
     "type": "module",
+    "sideEffects": false,
+    "main": "./dist/index.js",
+    "types": "./dist/index.d.ts",
     "exports": {
         ".": {
             "types": "./dist/index.d.ts",
             "import": "./dist/index.js"
         }
     },
-    "main": "./dist/index.js",
+    "publishConfig": {
-    "types": "./dist/index.d.ts",
+        "access": "public"
-    "files": [
+    },
-        "dist",
-        "README.md",
-        "LICENSE"
-    ],
     "scripts": {
         "build": "tsc -p tsconfig.build.json",
-        "check": "npm run check:oxlint && npm run check:oxfmt && npm run check:tsc && npm run check:cspell && npm run check:package && npm run check:outdated",
+        "check": "npm run check:oxlint && npm run check:oxfmt && npm run check:tsc && npm run check:cspell && npm run check:outdated",
-        "check:cspell": "cspell .",
+        "check:cspell": "cspell lint ${LEFTHOOK_FILES:-.}",
-        "check:outdated": "check-outdated",
+        "check:outdated": "check-outdated --ignore-pre-releases --ignore-packages @oxfmt/binding-darwin-arm64,@oxfmt/binding-darwin-x64,@oxfmt/binding-linux-arm64-gnu,@oxfmt/binding-linux-arm64-musl,@oxfmt/binding-linux-x64-gnu,@oxfmt/binding-linux-x64-musl,@oxfmt/binding-win32-x64-msvc,@oxlint/binding-darwin-arm64,@oxlint/binding-darwin-x64,@oxlint/binding-linux-arm64-gnu,@oxlint/binding-linux-arm64-musl,@oxlint/binding-linux-x64-gnu,@oxlint/binding-linux-x64-musl,@oxlint/binding-win32-x64-msvc",
-        "check:oxfmt": "oxfmt --check src",
+        "check:oxfmt": "oxfmt --check ${LEFTHOOK_FILES:-.}",
-        "check:oxlint": "oxlint src",
+        "check:oxlint": "oxlint ${LEFTHOOK_FILES:-src}",
-        "check:package": "sort-package-json --check",
         "check:tsc": "tsc --noEmit",
         "clean": "node -e \"fs.rmSync('dist', { recursive: true, force: true })\"",
-        "fix:oxfmt": "oxfmt src",
+        "fix:oxfmt": "oxfmt ${LEFTHOOK_FILES:-.}",
         "fix:oxlint": "oxlint --fix src",
-        "fix:package": "sort-package-json --write",
         "test": "npm run check:tsc && node --test --strip-types src/",
         "test:ci": "c8 --reporter=text --reporter=lcov --reporter=html node --test --strip-types src/",
         "test:unit": "node --test --strip-types src/",
         "use:git-commit-message": "cp commit-message-template .git/COMMIT_EDITMSG || true"
     },
     "devDependencies": {
-        "@oxfmt/binding-linux-x64-musl": "^0.66.0",
+        "@types/node": "^26.4.1",
-        "@oxlint/binding-linux-x64-musl": "^1.81.0",
+        "c8": "^12.0.0",
-        "@types/node": "^22.10.0",
+        "check-outdated": "^3.0.0",
-        "c8": "^10.1.3",
+        "cspell": "^10.2.1",
-        "check-outdated": "^2.13.0",
-        "cspell": "^8.19.3",
         "expect-type": "1.4.0",
-        "lefthook": "^1.11.12",
+        "lefthook": "^2.1.12",
         "oxfmt": "^0.66.0",
         "oxlint": "^1.81.0",
-        "sort-package-json": "^3.1.0",
         "tslib": "^2.8.1",
-        "type-fest": "^4.40.1",
+        "type-fest": "^5.9.0",
         "typescript": "^7.0.2"
     },
+    "optionalDependencies": {
+        "@oxfmt/binding-darwin-arm64": "^0.66.0",
+        "@oxfmt/binding-darwin-x64": "^0.66.0",
+        "@oxfmt/binding-linux-arm64-gnu": "^0.66.0",
+        "@oxfmt/binding-linux-arm64-musl": "^0.66.0",
+        "@oxfmt/binding-linux-x64-gnu": "^0.66.0",
+        "@oxfmt/binding-linux-x64-musl": "^0.66.0",
+        "@oxfmt/binding-win32-x64-msvc": "^0.66.0",
+        "@oxlint/binding-darwin-arm64": "^1.81.0",
+        "@oxlint/binding-darwin-x64": "^1.81.0",
+        "@oxlint/binding-linux-arm64-gnu": "^1.81.0",
+        "@oxlint/binding-linux-arm64-musl": "^1.81.0",
+        "@oxlint/binding-linux-x64-gnu": "^1.81.0",
+        "@oxlint/binding-linux-x64-musl": "^1.81.0",
+        "@oxlint/binding-win32-x64-msvc": "^1.81.0"
+    },
     "engines": {
         "node": ">=26"
-    },
-    "publishConfig": {
-        "access": "public"
     }
 }

project-specs.md

@@ -8,107 +8,225 @@ typescript-lib-starter-tiny => https://github.com/tmueller/typescript-lib-starte
 
 ## 1. Development Environment
 
-- **TypeScript**: Use strictest rules (via npm package "@tsconfig/strictest", additional strictures)
+- **TypeScript**: Use strictest practical rules. Inline in `tsconfig.json` (not
-- **EditorConfig**: Use `.editorconfig` from typescript-lib-starter-tiny
+  via `@tsconfig/strictest`). The rule set is: `strict`, `noImplicitAny`,
-- **Prettier**: For code formatting, integrated with ESLint
+  `noImplicitThis`, `alwaysStrict`, `strictNullChecks`, `strictFunctionTypes`,
-- **ESLint**: Strictest type-checked rules, integrated with Prettier
+  `strictBindCallApply`, `strictPropertyInitialization`, `noImplicitReturns`,
-- **Import Sorting**: Via Prettier or ESLint
+  `noFallthroughCasesInSwitch`, `noUncheckedIndexedAccess`, `noImplicitOverride`,
-- **cspell**: Basic spelling configuration
+  `noUnusedLocals`, `noUnusedParameters`, `forceConsistentCasingInFileNames`,
-- **Lefthook**: Pre-commit checks for:
+  `isolatedModules`, `verbatimModuleSyntax`.
-
+- **EditorConfig**: Use `.editorconfig` from typescript-lib-starter-tiny.
-   - Type checking
+- **oxfmt**: Rust-based formatter, Prettier-compatible. Replaces Prettier.
-   - Spelling
+  Config in `.oxfmtrc.json` (same shape as `.prettierrc`).
-   - Package sorting
+- **oxlint**: Rust-based linter. Replaces ESLint. Config in `.oxlintrc.json`
-   - Linting
+  with `typescript`, `unicorn`, `oxc`, `import` plugins. Categories enabled
-   - Formatting
+  as errors: `correctness`, `suspicious`, `restriction`. As warnings: `perf`,
-   - Outdated Packages
+  `style`. `nursery` is off.
+- **oxlint rules disabled by design** (in `.oxlintrc.json`):
+    - `eslint/no-undefined` — we use `undefined` as the no-match sentinel.
+    - `eslint/sort-keys` — handler/case order is semantic, not alphabetical.
+    - `eslint/id-length` — `T`, `R`, `U`, `V` are standard TS generics.
+    - `import/no-named-export` — false positive on library entry re-exports.
+      For `*.test.ts` files additionally: `no-unused-expressions` (for
+      `expectTypeOf(...)` calls), `no-empty-file` (we have a single import
+      per test file in some cases), `import/no-nodejs-modules` (we use
+      `node:test`/`node:assert`/`node:fs` intentionally), `eslint/no-magic-numbers`
+      (literals in tests are fine).
+- **Import sorting**: built into oxfmt (no separate plugin).
+- **cspell**: Basic spelling configuration. Words dictionary in `cspell.json`
+  covers tooling names (`oxlint`, `oxfmt`, `oxc`, `nodenext`,
+  `oxfmtrc`, `oxlintrc`, `EDITMSG`, `typescriptteam`,
+  `gitmoji`, `dbaeumer`, `msvc`) and a few library names (`tslib`,
+  `typefest`, `lefthook`).
+- **Lefthook**: Pre-commit checks (run in parallel, lefthook v2 schema).
+  Single source of truth for the underlying commands is in
+  `package.json#scripts`; the lefthook config only describes _what to
+  run on which files_. Hooks that should run on staged files
+  (`oxlint`, `oxfmt`, `cspell`) set the `LEFTHOOK_FILES` env var to
+  the staged-files list via a `sh -c` wrapper, and the npm script
+  uses `${LEFTHOOK_FILES:-<default>}` to default to the full project
+  when invoked manually:
+    - `pre-commit.commands.oxlint` (glob `*.{ts,tsx,js,jsx,mjs,cjs}`):
+      `sh -c 'LEFTHOOK_FILES="$0" npm run check:oxlint' {staged_files}`
+    - `pre-commit.commands.oxfmt` (glob `*.{ts,tsx,js,jsx,mjs,cjs}`):
+      `sh -c 'LEFTHOOK_FILES="$0" npm run check:oxfmt' {staged_files}`
+    - `pre-commit.commands.cspell`:
+      `sh -c 'LEFTHOOK_FILES="$0" npm run check:cspell' {staged_files}`
+    - `pre-commit.commands.typecheck`:
+      `npm run check:tsc` (no file args needed)
+      `outdated` is intentionally NOT a pre-commit check (it can flag
+      upstream patch releases that aren't actionable locally); it runs in
+      CI and via the explicit `lefthook run outdated` command.
 
 - **Additional Dev Dependencies**:
-
     - lefthook
-   - sort-package-json
     - check-outdated
+    - c8 (coverage for `node --test`)
+    - expect-type (type-level assertions in tests)
+    - oxfmt, oxlint (with their native bindings as `optionalDependencies`
+      so the correct binding is selected per platform automatically)
+    - typescript (TS 7)
+    - @types/node
+    - tslib (available for future runtime helper imports)
+    - type-fest (utility types)
 
 ## 2. Build & Test
 
-- **Build Tool**: Vite (ESM only, no CJS)
+- **Build Tool**: TypeScript 7 (`tsc`) — no bundler, no Vite. The build
-- **Testing**: Vitest
+  is a plain `tsc -p tsconfig.build.json` invocation that emits ESM
-- **TypeScript Build Output**: `dist` directory
+  JavaScript and `.d.ts` declarations to `dist/`. ESM only, no CJS.
-- **Additional Runtime Dependencies**:
+- **Testing**: Node's built-in `node --test` with `--strip-types` (Node
-   - tslib
+  22.6+, unflagged on Node 24/26). Test files are co-located with
-   - type-fest
+  source as `*.test.ts`. No Vitest.
+- **TypeScript Build Output**: `dist` directory (set in
+  `tsconfig.build.json#outDir`; `tsconfig.json` keeps `outDir` for
+  editor tooling but excludes tests from emission via
+  `tsconfig.build.json#exclude`).
+- **Import extensions**: Source uses `.ts` extensions in imports
+  (e.g. `from "./match.ts"`) so `node --strip-types` resolves them
+  at test time. TypeScript's `rewriteRelativeImportExtensions` (in
+  `tsconfig.build.json`) rewrites these to `.js` in the emitted
+  `dist/*` output, so consumers see conventional ESM imports.
+- **TypeScript Compiler Options Notes**:
+    - `allowImportingTsExtensions: true` is set in the root
+      `tsconfig.json` (works because the root config has `noEmit: true`).
+    - `rewriteRelativeImportExtensions: true` is set in
+      `tsconfig.build.json` to rewrite `.ts` to `.js` on emit.
+    - `module: nodenext`, `moduleResolution: nodenext` for ESM-first
+      Node packages.
+    - `verbatimModuleSyntax: true` enforces explicit `import type`.
+    - `target: es2024`, `lib: ["es2024"]` (Node 26 supports all ES2024
+      features natively).
+- **Additional Dev Dependencies** (for types and tests):
+    - `tslib` — available for runtime helper imports; not currently
+      used by source (kept for future use per the original spec).
+    - `type-fest` — utility types; not currently used by source
+      (kept for future use per the original spec).
+    - `@types/node` — types for `node:test`, `node:assert`, `node:fs`.
+- **Node Version**: `>=26` (engines field). Pinned via `.node-version`
+  for fnm/nvm/volta/mise auto-switching and CI
+  (`actions/setup-node@v4` with `node-version-file: .node-version`).
 
 ## 3. Project Structure & Files
 
-- __.gitignore__: Ignore `dist`, `node_modules`, and other common files
+- **.gitignore**: Ignore `dist`, `node_modules`, `coverage`, and other
-- **.npmignore**: Ignore `src` and other non-dist files
+  common files.
-- **LICENSE**: MIT
+- **.node-version**: Single line containing the Node major version
-- **README.md**: Scaffolded
+  (currently `26`). Used by version managers and CI.
-- **commit-message-template**: From typescript-lib-starter-tiny
+- **.npmignore**: Ignore `node_modules/`, `coverage/`, `*.log`,
-- **Target Environments**: Browser and latest LTS Node.js
+  `*.tsbuildinfo`, `src/`, `.vscode/`, `.editorconfig`,
-- **No React, No CJS, ESM only**
+  `.oxfmtrc.json`, `.oxlintrc.json`, `.node-version`, `cspell.json`,
+  `lefthook.yml`, `commit-message-template`.
+  (Note: `dist/` is included via `package.json#files`, not by absence
+  from `.npmignore`.)
+- **.oxfmtrc.json**: oxfmt configuration (Prettier-shaped).
+- **.oxlintrc.json**: oxlint configuration.
+- **.oxlintrc.json + .oxfmtrc.json** replace the old `.eslintrc.cjs`
+  and `.prettierrc`.
+- **LICENSE**: MIT.
+- **README.md**: Scaffolded.
+- **commit-message-template**: From typescript-lib-starter-tiny.
+- **Target Environments**: Node 26 LTS only (no browser target; this
+  is a pure Node library, no DOM, no DOM lib in tsconfig).
+- **No React, No CJS, ESM only**.
 
 ## 4. Automation & Quality
 
-- **Version Automation**: Use standard `npm version` for versioning
+- **Version Automation**: Use standard `npm version` for versioning.
-- **Unused Dependency Check**: Use `check-outdated` with config
+- **Unused Dependency Check**: Use `check-outdated` (devDep, runs in CI
-- **No commitlint, no conventional commits**
+  and via the explicit `lefthook run outdated` command).
+- **No commitlint, no conventional commits**. Commits use gitmoji
+  prefixes (e.g. `:sparkles:`, `:wrench:`, `:bug:`, `:fire:`,
+  `:white_check_mark:`, `:tada:`) for at-a-glance categorization.
 
-## 5. Scripts (Clustered as in typescript-lib-starter-tiny, named similarly)
+## 5. Scripts
 
 ### SETUP
 
-- `use:git-commit-message`: Set up commit message template (if needed)
+- `use:git-commit-message`: Set up commit message template (if needed).
 
 ### TEST
 
-- `test`: Run typecheck and all tests
+- `test`: Run `tsc --noEmit` then `node --test --strip-types src/`.
-- `test:unit`: Run unit tests with Vitest
+- `test:unit`: Run unit tests with `node --test --strip-types src/`
-- `test:ci`: Run tests in CI mode (with coverage, fail-fast)
+  (no preceding typecheck).
+- `test:ci`: Run tests in CI mode with c8 coverage (text + lcov + html
+  reporters), uploading `coverage/` as an artifact.
 
 ### BUILD
 
-- `build`: Build the project using Vite
+- `build`: Build the project using `tsc -p tsconfig.build.json`
+  (emits `dist/*.js` + `dist/*.d.ts` + sourcemaps, with `.ts`
+  imports rewritten to `.js`).
 
 ### CLEAN
 
-- `clean`: Clean build output
+- `clean`: Remove `dist/` via `node -e "fs.rmSync('dist', {recursive:true, force:true})"`.
-- `clean:build`: Remove dist directory
+  (Replaces `clean:build` from the original spec — same effect,
+  no `rimraf` dep needed.)
 
 ### CHECK
 
-- `check`: Run all checks (lint, spell, typecheck, import/package sort, outdated)
+- `check`: Run all checks in order — `check:oxlint`, `check:oxfmt`,
-- `check:eslint`: Run ESLint
+  `check:tsc`, `check:cspell`, `check:outdated`.
-- `check:prettier`: Check formatting with Prettier
+- `check:oxlint`: `oxlint ${LEFTHOOK_FILES:-src}` — lints `src/`
-- `check:cspell`: Run cspell
+  by default; when invoked from the lefthook pre-commit hook with
-- `check:tsc`: TypeScript typecheck (no emit)
+  `LEFTHOOK_FILES` set to the staged-files list, lints only those
-- `check:package`: Check package.json sort
+  files. This is the single source of truth for the oxlint command
-- `check:outdated`: Check for unused/outdated dependencies
+  and is shared between the manual `npm run check` and the pre-commit
+  hook. oxlint only understands JS/TS-family languages, so config
+  files (JSON/YAML/Markdown) are intentionally outside its scope;
+  they are checked only by oxfmt.
+- `check:oxfmt`: `oxfmt --check ${LEFTHOOK_FILES:-.}` — formats the
+  whole project (`.`) by default, including JS/TS, JSON/JSONC,
+  YAML, Markdown, MDX and other supported file types. From lefthook
+  pre-commit, the `LEFTHOOK_FILES` env var scopes to the staged
+  files matching `*.{ts,tsx,js,jsx,mjs,cjs,json,jsonc,yaml,yml,md,mdx}`.
+  Built-in `sortPackageJson: true` keeps `package.json` keys
+  alphabetized (replaces the former `sort-package-json` tool).
+  Built-in import sorting (enabled via `sortImports: true`) replaces
+  any external import-sort plugin.
+- `check:tsc`: `tsc --noEmit`.
+- `check:cspell`: `cspell lint ${LEFTHOOK_FILES:-.}` — walks the
+  project root by default; from lefthook, only the staged files.
+- `check:outdated`: `check-outdated --ignore-pre-releases --ignore-packages @oxfmt/binding-*,@oxlint/binding-*`. The oxc native bindings are declared as `optionalDependencies` so the correct one is selected per platform automatically; the `*`-platform bindings show as "not installed" on the current platform and are explicitly ignored here.
 
 ### FIX
 
-- `fix`: Run all fixers (eslint, prettier, package sort)
+- `fix:oxlint`: `oxlint --fix src`.
-- `fix:eslint`: Auto-fix ESLint issues
+- `fix:oxfmt`: `oxfmt ${LEFTHOOK_FILES:-.}` — same scoping as
-- `fix:prettier`: Auto-fix formatting with Prettier
+  `check:oxfmt` (whole project by default, staged files from
-- `fix:package`: Auto-fix package.json sort
+  lefthook). Writes changes in place.
+  (There is no `fix` aggregator in the scripts; run the `fix:*` scripts
+  individually.)
 
 ### HOOKS
 
-- Lefthook will run relevant scripts on staged files for pre-commit (typecheck, lint, spell, sort, format, check:outdated)
+- Lefthook runs the relevant `check:*` scripts on staged files in
+  parallel for pre-commit. See `lefthook.yml`.
 
 ---
 
 ## 6. Repository & CI/CD
 
-- **Repository**: Hosted on GitHub
+- **Repository**: Hosted on GitHub.
-- **Build Pipeline**: Use GitHub Actions for CI/CD
+- **Build Pipeline**: GitHub Actions (`.github/workflows/ci.yml`).
-   - On push and pull request: run build, lint, typecheck, test:ci, spell, check:outdated
+    - `build` job on push and pull_request to `main` and on
-   - On release (tagged commit): publish to npm
+      `workflow_dispatch`. Steps: `actions/checkout@v4`,
+      `actions/setup-node@v4` (with `node-version-file: .node-version`,
+      `cache: npm`), `npm ci`, `npm run build`, `npm run check`,
+      `npm run test:ci`, then upload `coverage/` as an artifact.
+    - `publish` job: only on `refs/tags/*`, depends on `build`. Steps:
+      `actions/checkout@v4`, `actions/setup-node@v4` (with
+      `node-version-file: .node-version` and `registry-url`),
+      `npm ci`, `npm run build`, `npm publish --access public`
+      with `NODE_AUTH_TOKEN` from secrets.
 
 ## 7. Versioning & Publishing
 
-- **Version Update**: Use `npm version` to bump version after merging to main and before publishing
+- **Version Update**: Use `npm version` to bump version after merging
-- **Publishing to npm**: Only publish from CI on tagged commits (e.g., after version bump and release notes)
+  to main and before publishing.
+- **Publishing to npm**: Only publish from CI on tagged commits.
 - **Recommended Workflow**:
     1. Develop and merge PRs to main
     2. Run all checks via CI
@@ -125,40 +243,42 @@ typescript-lib-starter-tiny => https://github.com/tmueller/typescript-lib-starte
 - adt
 - typescript
 
-> The library is for pattern matching (not regex), similar to F#'s pattern matching, for TypeScript/ESM environments.
+> The library is for pattern matching (not regex), similar to F#'s
+> pattern matching, for TypeScript/ESM environments.
 
 ## 9. Code Coverage
 
-- **Configuration**:
+- **Tool**: c8 (V8-native coverage, no instrumentation step).
+- **Configuration**: c8 has no project config; the report shape is
+  pinned in the `test:ci` script:
 
-```ts
+```jsonc
-import { defineConfig } from 'vitest/config';
+"test:ci": "c8 --reporter=text --reporter=lcov --reporter=html node --test --strip-types src/"
-export default defineConfig({
-  test: {
-    coverage: {
-      reporter: ['text', 'html', 'lcov'],
-      include: ['src/**/*.ts'],
-      exclude: ['src/**/*.test.ts', 'test/**'],
-    },
-  },
-});
 ```
 
-- Coverage reports: text summary, HTML, and lcov formats
+- **Reporters**: text summary, HTML, and lcov (matching the original
-
+  spec).
-- Add coverage thresholds if desired
+- **CI**: `coverage/` is uploaded as a workflow artifact via
-
+  `actions/upload-artifact@v4` (see `.github/workflows/ci.yml`).
-- **CI**: Ensure coverage is generated and optionally uploaded as an artifact or checked for minimum thresholds
+- **Optional**: Coverage thresholds can be added in c8 config when the
+  library surface stabilizes.
 
 ## 10. Source Structure & Tree Shaking
 
-- **Source Directory**: All source code resides in `src/` and is exported via `src/index.ts`.
+- **Source Directory**: All source code resides in `src/` and is
+  exported via `src/index.ts`.
 - **Configuration**:
-   - Ensure `sideEffects: false` in `package.json`
+    - `sideEffects: false` in `package.json` (set).
-   - Use ESM-only exports
+    - ESM-only exports; `package.json#exports` field maps `.` to
-   - Avoid top-level side effects in modules
+      `{"types": "./dist/index.d.ts", "import": "./dist/index.js"}`.
-   - Prefer explicit exports in `index.ts` for best results
+    - Avoid top-level side effects in modules.
-- the human will implement the source code
+    - Explicit re-exports in `index.ts` for best results.
+- Source structure (current):
+    - `src/index.ts` — public barrel.
+    - `src/match.ts` — `match(value).with(...).exhaustive() / .otherwise(...)` builder.
+    - `src/pattern.ts` — `P.literal`, `P.type`, `P.when`, `P.any`, `P.shape` constructors and the `Matcher<T>` interface.
+    - `src/index.test.ts` — runtime + type-level tests using `node --test` + `expect-type`.
+- The human will implement the source code.
 
 ## 11. Included Templates from typescript-lib-starter-tiny
 
@@ -207,90 +327,137 @@ Resolves #...
 #    Can use multiple lines with "-" for bullet points in body
 ```
 
-### README.md Structure (to scaffold)
+### README.md Structure (scaffolded)
 
 - Project title and description
 - Development
     - Build: `npm run build`
     - Test: `npm run test`, `npm run test:ci`
-  - Checks: `npm run check`, `npm run fix`
+    - Checks: `npm run check`, `npm run fix:oxfmt`, `npm run fix:oxlint`
+- Tooling section listing TypeScript 7, node --test, c8, oxlint, oxfmt,
+  cspell, lefthook
+- Requirements: Node.js >= 26
 - VSCode integration
     - Debugging
     - Running tests
-- Document workflows like 
+    - oxc.oxc-vscode provides oxlint and oxfmt in-editor
-   - Version updates
+- Workflows
-   - Changelog automation
+    - Version updates via `npm version`
-   - Publishing
+    - Publishing via GitHub Actions on tagged commits
 - Contribution guidelines
     - Commit signing (GPG)
-  - How to set up commit message template
+    - How to set up commit message template (`npm run use:git-commit-message`)
     - Reference to commit-message-template
+    - Type-level tests use `expect-type`'s `expectTypeOf(...)` inside
+      `node --test` cases
 
 ## 12. Project Initialization & Commit Strategy
 
-- Start by initilizing git with a main branch
+- Start by initializing git with a `main` branch.
-- Initial commit: add an empty README.md
+- Initial commit: empty README + LICENSE.
-- create a feature branch: `feature/setup`
+- Create a feature branch: `feature/setup`.
-- For each technology or tool added (and its configuration), create a separate commit:
+- For each technology or tool added (and its configuration), create a
-  - Prepend each commit message with a matching gitmoji (e.g., :sparkles: for new features, :wrench: for config, etc.)
+  separate commit:
-  - Example commit messages:
+    - Prepend each commit message with a matching gitmoji (e.g.
-    - :tada: Initial commit with empty README
+      `:sparkles:` for new features, `:wrench:` for config,
-    - :sparkles: Configured Vite (Vite-specific setup)
+      `:bug:` for fixes, `:fire:` for removals,
-    - :sparkles: Configured TypeScript (may be merged with Vite if dependent)
+      `:white_check_mark:` for tests, `:tada:` for initial commit).
-    - :wrench: Configured ESLint
+    - Example commit messages used in this project:
-    - :wrench: Configured Prettier
+        - `:tada: Initial commit with empty README`
-    - ...and so on for each technology/tool
+        - `:wrench: Track .vscode/settings.json for workspace settings`
-- Each commit should include only the relevant files and configuration for that technology/tool
+        - `:construction_worker: Added GitHub Actions workflow for CI/CD`
-- This approach ensures a clean, understandable project history and makes it easy to review or revert specific setup steps
+        - `:test_tube: Added Vitest configuration with coverage` (later removed)
-
+        - `:sparkles: Scaffolded src/index.ts entry point for library code`
+        - `:wrench: Replace Vite/Vitest with TypeScript 7 and node --test`
+        - `:wrench: Replace ESLint and Prettier with oxlint and oxfmt`
+        - `:fire: Remove Vite scaffold leftovers`
+        - `:sparkles: Add initial pattern-matching API`
+        - `:white_check_mark: Add expect-type for type-level tests`
+        - `:wrench: Declare Node 26 as the supported runtime`
+        - `:bug: Use .ts extensions in imports for node --strip-types`
+        - `:wrench: Remove Prettier from editor formatter config`
+- Each commit should include only the relevant files and configuration
+  for that technology/tool. This approach ensures a clean, understandable
+  project history and makes it easy to review or revert specific setup
+  steps.
 
 ## 13. Changelog Automation
 
-- Use a tool like standard-version or changesets to automate changelog generation from commit messages or PRs.
+- Not currently configured. The intended workflow, when adopted, is a
-- Ensure changelog is updated as part of the release process.
+  changesets-driven release process: feature PRs include a changeset,
+  which gets consumed by a release workflow, producing a `CHANGELOG.md`
+  and a version bump on merge to main.
+- The changelog should be updated as part of the release process.
 
 ## 14. Publishing Public
 
-- Configure npm publishing to be public by default.
+- npm publishing is configured to be public by default.
-- Add `"publishConfig": { "access": "public" }` to package.json.
+- `publishConfig: { "access": "public" }` is set in `package.json`.
-- Ensure CI/CD pipeline publishes with public access.
+- The CI/CD pipeline publishes with `--access public` on tagged commits.
 
 ## 15. VSCode Integration
 
-- Add a `.vscode/settings.json` with the following content:
+- `.vscode/settings.json` uses `oxc.oxc-vscode` as the default
+  formatter for `[typescript]`, `[javascript]`, `[json]`, `[jsonc]`,
+  `[markdown]`, `[mdx]`, and `[yaml]` (oxfmt under the hood).
 
 ```json
 {
     "typescript.tsdk": "node_modules/typescript/lib",
+    "js/ts.tsdk.path": "node_modules/typescript/lib",
     "[typescript]": {
-        "editor.defaultFormatter": "esbenp.prettier-vscode",
+        "editor.defaultFormatter": "oxc.oxc-vscode",
+        "editor.formatOnSave": true
+    },
+    "[javascript]": {
+        "editor.defaultFormatter": "oxc.oxc-vscode",
         "editor.formatOnSave": true
     },
     "[json]": {
-        "editor.defaultFormatter": "esbenp.prettier-vscode",
+        "editor.defaultFormatter": "oxc.oxc-vscode",
+        "editor.formatOnSave": true
+    },
+    "[jsonc]": {
+        "editor.defaultFormatter": "oxc.oxc-vscode",
+        "editor.formatOnSave": true
+    },
+    "[markdown]": {
+        "editor.defaultFormatter": "oxc.oxc-vscode",
         "editor.formatOnSave": true
     },
     "[mdx]": {
-        "editor.defaultFormatter": "esbenp.prettier-vscode",
+        "editor.defaultFormatter": "oxc.oxc-vscode",
         "editor.formatOnSave": true
     },
-    "editor.defaultFormatter": "esbenp.prettier-vscode",
+    "[yaml]": {
-    "editor.formatOnSave": true,
+        "editor.defaultFormatter": "oxc.oxc-vscode",
-    "[javascript]": {
+        "editor.formatOnSave": true
-        "editor.defaultFormatter": "esbenp.prettier-vscode",
+    },
+    "editor.defaultFormatter": "oxc.oxc-vscode",
     "editor.formatOnSave": true
-    }
 }
 ```
 
-- Add `.vscode/extensions.json` with recommended extensions:
+- `.vscode/extensions.json` recommends:
-  - `esbenp.prettier-vscode` (Prettier)
+    - `oxc.oxc-vscode` (oxlint + oxfmt, replaces eslint/prettier/vitest)
-  - `dbaeumer.vscode-eslint` (ESLint)
     - `streetsidesoftware.code-spell-checker` (cspell)
-  - `vitest.explorer` (for test integration)
+    - `typescriptteam.native-preview` (TypeScript 7 nightly support;
-  - TODO: Native test extension with node test runner
+      replaces the older `ms-vscode.vscode-typescript-next`)
-  - `ms-vscode.vscode-typescript-next` (for latest TS features, optional)
 
-- Add `.vscode/tasks.json` for common tasks (optional):
+```json
-  - Build, test, lint, typecheck, format, spell, check:outdated
+{
-- Ensure VSCode uses workspace TypeScript version and Prettier for formatting
+    "recommendations": [
+        "oxc.oxc-vscode",
+        "streetsidesoftware.code-spell-checker",
+        "typescriptteam.native-preview"
+    ]
+}
+```
+
+- `.vscode/tasks.json` is not currently provided; common tasks
+  (build, test, lint, typecheck, format, spell, check:outdated) are
+  run via the npm scripts in `package.json` from the integrated
+  terminal.
+- VSCode uses the workspace TypeScript version via
+  `typescript.tsdk` (and the explicit `js/ts.tsdk.path`), with
+  `oxc.oxc-vscode` for formatting and linting.

src/index.test.ts

@@ -1,6 +1,8 @@
-import { test } from "node:test";
 import { strict as assert } from "node:assert";
+import { test } from "node:test";
+
 import { expectTypeOf } from "expect-type";
+
 import { match, P, type Matcher } from "./index.ts";
 
 test("match returns a builder", () => {