Files
tiny-pattern-ts/development/tooling.md
T
tmu 94ccc16963 ➕ Add the LSP protocol dependency
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.
2026-09-18 07:14:45 +00:00

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# Tooling
Every tool below was chosen and configured deliberately. The commands a
contributor runs are in [CONTRIBUTING.md](../CONTRIBUTING.md) and the versions
in [package.json](../package.json).
## Tool inventory
- **TypeScript 7** — type checker and build (`tsc`).
- **node --test** + `--strip-types` — test runner.
- **c8** — coverage for `test:ci`.
- **oxlint** — Rust linter, type-aware via **oxlint-tsgolint** (typescript-go).
- **oxfmt** — Rust formatter (Prettier-compatible) for JS/TS, JSON/JSONC, YAML,
Markdown, MDX, and more; its `package.json` key sorting replaces
`sort-package-json`.
- **cspell** — spell checking.
- **knip** — unused dependencies, exports, and files.
- **check-outdated** — dependencies behind the registry; exits non-zero when any
is outdated.
- **publint** — validates `package.json` for ESM publishing.
- **@arethetypeswrong/cli** (`attw`) — validates `.d.ts` against module-resolution
scenarios.
- **lefthook** — git hooks.
- **@spences10/pi-lsp** — read-only LSP code intelligence for AI agents
(project-local `.pi/settings.json`); talks to this repo's TypeScript 7 via
`tsc --lsp --stdio`.
- **vscode-languageserver-protocol** — LSP client and protocol types for the
autocomplete test helper (`src/util/__tests__/lsp-completion.ts`).
When each runs is in
[CONTRIBUTING.md § Feedback tiers](../CONTRIBUTING.md#feedback-tiers).
## TypeScript and build
### One type-check config, one emit config
#### Decision (2026-09)
`tsconfig.json` extends `@tsconfig/strictest` + `@tsconfig/node26`.
`tsconfig.build.json` adds the emit-only options (`declaration`, `sourceMap`,
`inlineSources`, `outDir`, `target: es2024`,
`rewriteRelativeImportExtensions: true`) and excludes test files.
#### Why
- The editor and CI type-check from one config while the build emits from the
other, so a test file cannot leak into `dist/`.
- `inlineSources` embeds the original TypeScript in `dist/*.js.map`, so
debuggers map into `src/` without it being shipped.
- `declarationMap` stays off: a `.d.ts.map` cannot embed source and would
dangle.
### The build starts from an empty `dist/`
#### Decision (2026-09)
`npm run build` runs a `prebuild` hook that empties `dist/`.
#### Why
- `tsc` does not prune orphaned emit output — dropping `declarationMap` left
stale `*.d.ts.map` files — so reproducibility needs an empty `dist/`.
- `prebuild` removes only `dist`; the manual `clean` resets `dist` + `coverage`,
so a local coverage report survives a build.
### Source imports use `.ts` extensions
#### Decision (2026-09)
Source imports use `.ts`, never `.js`.
#### Why
- `node --strip-types` resolves the `.ts` form at test time.
- `rewriteRelativeImportExtensions` rewrites them to `.js` in the emitted
JavaScript.
- The emitted `.d.ts` keep the `.ts` specifier, which TypeScript >= 5.0 resolves
(see [README § Requirements](../README.md#requirements)), so no
post-processing step is needed.
#### Rejected
- "Pre-fixing" an import to `.js`: it breaks the inner `node --strip-types`
loop.
## Linting and formatting
### Type-aware oxlint is a config property
#### Decision (2026-09)
Type-aware oxlint is enabled via `options.typeAware: true` in `.oxlintrc.json`
(powered by `oxlint-tsgolint`).
#### Why
- The script commands stay clean — no CLI flag.
- A config property cannot be forgotten on one call site.
#### Rejected
- A CLI flag in the `check:oxlint` / `fix:oxlint` scripts: it puts the mode in
two places and invites them to drift.
### `oxlint-disable` directives live next to the code
#### Decision (2026-09)
A type-aware rule that false-positives is silenced with a source-level
`oxlint-disable` directive (see `src/primitive.ts`,
`src/primitive.test.ts`), not by turning the rule off in `.oxlintrc.json`.
#### Why
- The disable sits next to the code it silences, visible to anyone reading the
source.
- The rule stays on everywhere else, so only the mis-firing line is exempted.
#### Rejected
- A project-wide disable in `.oxlintrc.json` for a false positive: it hides the
exemption from the reader of the affected code and switches the rule off
repo-wide for a one-site problem.
#### Known issue
- A source-level disable is a _human_ last resort. AI agents must not add one;
they fix the type at its root (see [AGENTS.md § Never do](../AGENTS.md#never-do)).
### Unwanted stylistic rules are turned off in the config
#### Decision (2026-09)
A stylistic rule the project rejects is `"off"` in the `.oxlintrc.json` `rules`
map, not silenced at a use site. Current entries: `eslint/capitalized-comments`
(comments may start lowercase) and `eslint/no-ternary` (ternaries are allowed),
joining the oxfmt-superseded rules already off.
#### Why
- The rule is wrong for the whole project, not mis-firing at one site, so there
is no line to annotate.
- Keeping the two mechanisms separate keeps a source-level `oxlint-disable`
meaningful: it marks a lone exception.
#### Rejected
- A source-level `oxlint-disable` per use: the same exemption repeated at every
site, and oxfmt can move the site.
### `check:tsc` runs first
#### Decision (2026-09)
`check:tsc` runs first in the `npm run check` chain.
#### Why
- A type error short-circuits the rest, which is faster than running
oxlint/oxfmt and failing on `tsc` at the end.
### `.editorconfig` is a fallback, not a gate
#### Decision (2026-09)
`.editorconfig` exists for editor compatibility; where both apply,
`.oxfmtrc.json` is authoritative.
#### Why
- `.editorconfig` covers the files oxfmt does not format: shell scripts,
dotfiles, `LICENSE`, the commit-message template, and git's `COMMIT_EDITMSG`
buffer.
- oxfmt is the formatter; the overlapping keys only keep non-oxfmt editors close
to the formatted result, so they cannot disagree with the checker.
## Static analysis and packaging
### `knip` omits the `types` category
#### Decision (2026-09)
`knip --include dependencies,exports,files` omits the `types` category.
#### Why
- `types` produces systematic false positives for libraries whose exported types
are part of the public API.
- The narrower scope keeps the signal high without config-file boilerplate.
### `maintain:outdated` ignores `@types/node`
#### Decision (2026-09)
Pass `--ignore-packages @types/node`.
#### Why
- DT pins `@types/node`'s `latest` dist-tag to LTS (22.x); current-line types
ride other tags. Scan sees latest < installed — permanent "reverted", exit
1, zero signal. `--ignore-pre-releases` no help: 22.20.3 is stable.
#### Rejected
- `--types major,minor,patch`: hides real reverted reports elsewhere.
- `@types/node@26.*`: tag stays wrong across majors; un-pin per bump = ritual.
#### Known issue
- A genuinely behind `@types/node` goes unreported; match it to
`.node-version` by hand.
### `attw` targets ESM-only
#### Decision (2026-09)
`attw --profile esm-only` is used.
#### Why
- The package is intentionally ESM-only (no CommonJS shim), so CJS resolution
scenarios are out of scope by design, not a bug.
### `tslib` is deliberately not used
#### Decision (2026-09)
`tslib` is not a dependency.
#### Why
- `tslib` is a runtime helper for old ES3/ES5 targets; this project targets
ES2024.
## Git hooks and script wiring
### `LEFTHOOK_FILES` scopes commands to staged files
#### Decision (2026-09)
The pre-commit hook sets `LEFTHOOK_FILES` to the staged-files list, and the
affected scripts use `${LEFTHOOK_FILES:-<default>}` to default to the whole
project.
#### Why
- It keeps `package.json#scripts` the single source of truth; `lefthook.yml`
only says what to run on which files.
- The same script works by hand (whole project) and staged (scoped), so there is
no second command to maintain.
## Language server tooling
### `vscode-languageserver-protocol` backs the autocomplete helper
#### Decision (2026-09)
The autocomplete helper (`src/util/__tests__/lsp-completion.ts`) drives
`tsc --lsp --stdio` through `vscode-languageserver-protocol`'s
`createMessageConnection` and its typed request / notification objects, instead
of a hand-rolled JSON-RPC client.
#### Why
- Framing, `Content-Length` parsing, the pending-request map and server-request
dispatch are protocol plumbing the helper only reimplemented; the official
client owns them and tolerates the server's `string | number` ids.
- `InitializeRequest`, `CompletionRequest`, `DidOpenTextDocumentNotification`,
… carry their parameter and result types, so `CompletionList` / `CompletionItem`
replace the helper's ad-hoc shape guards.
- The `./node` entry re-exports `vscode-jsonrpc/node`, so one devDependency
supplies both the transport and the protocol types. It is test-only and never
ships (`files` publishes `dist/` only).
#### Rejected
- `vscode-languageclient`: the editor-side client with a full feature registry
— far more than a test helper needs.
- Generic JSON-RPC (`jsonrpc-lite`, `jayson`): still no LSP types, so they
replace framing only and leave the typed protocol surface unimplemented.
- Keeping the hand-rolled client: the low-level shape is the maintenance cost
the helper exists to remove, and it must be re-audited against the server.
## Editor and agent tooling
### VSCode integration
- Recommended extensions are in
[.vscode/extensions.json](../.vscode/extensions.json) (oxc, cspell, TypeScript
native-preview, EditorConfig, todo-tasks).
- TypeScript 7 runs via the `typescriptteam.native-preview` extension.
- The oxc extension provides oxlint squiggles and oxfmt format-on-save;
`.vscode/settings.json` pins it per language so a local `[language]` formatter
setting cannot override the project's choice.
### `@spences10/pi-lsp` is pinned and read-only
#### Decision (2026-09)
`@spences10/pi-lsp` is pinned to `0.0.46` and used read-only.
#### Why
- It inspects `node_modules/typescript`, sees major >= 7 with no
`lib/tsserver.js` (true of the `typescript-go` / `tsgo` port), and spawns the
repo's own `tsc --lsp --stdio` — no `typescript-language-server` dependency is
needed.
- Earlier releases (`<= 0.0.10`) hard-wire to `typescript-language-server
--stdio` and are TS6-only.
- It is _intermediate_ agent feedback (hover, references, definition, symbols,
diagnostics), with no rename / code-action / apply-edit surface, and is never a
gate — `npm run check` / `verify` are.
- `.pi/settings.json` is the committed declaration; `.pi/npm/` is a gitignored
install cache that pi recreates on a trusted startup (running `npm install`
for any missing project package), so it is deliberately not tracked.