- Install expect-type@1.4.0 (devDependency)
- New src/index.test.ts exercises the public API with both runtime
assertions (node:assert/strict inside node:test) and type-level
assertions (expectTypeOf().toEqualTypeOf, toMatchTypeOf, toHaveProperty)
- Tests are excluded from tsc -p tsconfig.build.json (no .d.ts pollution
in dist/)
- Type-level checks happen during tsc --noEmit (run by 'npm run check' and
the test script); expectTypeOf assertions have no runtime side effect,
so they pair naturally with node --test in the same test() blocks
- cspell: add EDITMSG to dictionary (used in commit-message-template path)
- oxlint test-file overrides: silence no-nodejs-modules (we use node:
builtins) and no-magic-numbers (literals in tests are fine)
Coverage:
- match() returns a builder with with/exhaustive/otherwise
- P.literal narrows to its literal type, P.type to its typeof target
- exhaustive() returns the union of handler return types
- otherwise() falls back when no case matches
- exhaustive() throws when no case matches
Introduce the core builder and pattern constructors:
- match(value): chain .with(pattern, handler) and terminate with
.exhaustive() (throws on no match) or .otherwise(handler).
- P.literal, P.type, P.when, P.any, P.shape for pattern construction.
- Each pattern is a Matcher<T> whose matches acts as a type guard, so
handler parameters are narrowed to the matched type.
The MatchBuilder accumulates handlers and returns a new builder per
.with() call (immutable chaining); finalization runs the cases in order
and returns the first match's handler result.
TypeScript configuration relaxed in .oxlintrc.json:
- Disable eslint/no-undefined (we use undefined as the no-match sentinel)
- Disable eslint/sort-keys (handler order matters; alphabetical would
be wrong)
- Disable eslint/id-length (T/R/U/V generics are standard TS convention)
- Disable import/no-named-export (false positive for library entry points)
Verified:
- tsc --noEmit passes with strict + noUncheckedIndexedAccess
- tsc -p tsconfig.build.json emits dist/*.js + .d.ts + sourcemaps
- node -e "import('./dist/index.js')" loads and exposes { match, P }
- Delete public/vite.svg, src/typescript.svg, src/style.css
- Empty public/ directory removed
- .npmignore: drop 'public/' entry (directory no longer exists), add
.oxlintrc.json and .oxfmtrc.json to ignore list
- cspell: add .oxfmtrc, .oxlintrc, .sortpackagerc to dictionary so
config-file name references aren't flagged
- lefthook: drop 'outdated' from pre-commit (kept in commands block for
explicit CI invocation); it shouldn't block commits for being behind on
upstream patch releases
- Use tsc 7 for build (vite no longer needed for a Node library)
- Use node --test with --experimental-strip-types for tests (vitest dropped)
- Use c8 for coverage instead of vitest's built-in coverage
- Add tsconfig.build.json separating typecheck from emit config
- Drop DOM lib, add strict noUncheckedIndexedAccess/noImplicitOverride
- Pin engines.node to >=22.6 (required for --experimental-strip-types)
- Update CI to Node 24 LTS (unflagged strip-types)
- Add @types/node for node:test / node:assert types
tmu
Thomas Müller