[CyberDex]

What

Makes the project compile under TypeScript 7, the native compiler rewrite, and adds the checks that keep the published declarations usable there.

Rebased on main. #285 landed the ScrollBox NodeJS.Timeout fix independently, so that part of this branch merged away — @pixi/[email protected] ships clean of it. What remains is the part main still lacks.

The blocker

TypeScript 7 removed moduleResolution: "node" (node10), and main still sets it. The compiler refuses the project before reading a single source file:

tsconfig.json(9,29): error TS5108: Option 'moduleResolution=node10' has been removed.

The sources are bundled by rollup, so "bundler" is the mode that matches how they're consumed, and it needs no changes to import specifiers (unlike node16/nodenext). With that one line changed, main's sources — Drawer, the input package, Signal and all — type-check clean on 7.0.2.

Why TypeScript 7 is installed alongside 5.x, not instead of it

typescript@7 ships a native binary and a thin wrapper — the classic JS compiler API is gone (its only main export is lib/version.cjs). eslint, ts-jest and storybook's fork-ts-checker all reach for that API, so a straight bump takes the toolchain down. Confirmed by trying it:

TypeError: Failed to load plugin '@typescript-eslint': Cannot read properties of undefined (reading 'Intrinsic')
    at .../ts-api-utils/lib/index.cjs:779:57

So 7.x goes in under an alias:

"typescript": "^5.8.3",
"typescript-7": "npm:typescript@^7.0.2"

node_modules/.bin/tsc keeps resolving to 5.x (verified deterministic across install orders and npm ci), so xs lint, xs types and xs build are untouched. The new scripts invoke 7.x by path. Nothing new is published — the alias is a devDependency, and the platform binaries are optional entries in the lockfile, so each CI runner only downloads its own.

What's checked now

• npm run types — sources, through both compilers.
• npm run types:dist (new CI step, after build) — the built declarations, two ways.

Content. consumer.ts imports the root entry with skipLibCheck off and no ambient @types. That's what gives the check teeth: a bad type on a protected member only ever surfaces as a diagnostic inside a .d.ts file, so skipLibCheck: true hides it completely — which is exactly how the NodeJS.Timeout leak reached npm and had to be fixed reactively in #285. Since the root entry re-exports every module, naming it pulls the whole declaration output into the program.

Wiring. #286 added seventeen per-component subpath exports, each promising its own types target, and nothing verifies those point at files that were built. A typo in a subpath's types doesn't fail a build — the import quietly resolves to any in the consumer's project. check.mjs now walks the exports map and fails on any entry whose declaration is missing.

npm run release runs the check between build and publish, so this guards the path the bug actually escaped through, not just pull requests.

Both failure modes verified:

Scenario	Exit
clean	0
NodeJS.Timeout reintroduced into lib/ScrollBox.d.ts	1
exports entry pointing at a missing declaration	1

Because skipLibCheck is off, dependency declarations get checked too — 181 diagnostics against the pinned pixi.js 8.6.2, which this repo can't fix. check.mjs counts and reports them but only fails on diagnostics from files inside the repo, so an upstream regression can't block a release here.

Unrelated one-liner, but it's blocking CI

Main's lint is currently red, and it takes every PR with it: scripts/build-umd.mjs from #286 reports to stdout, and xs lint runs --max-warnings 0.

/home/runner/work/ui/ui/scripts/build-umd.mjs
  57:1  warning  Unexpected console statement  no-console
✖ 1 problem (0 errors, 1 warning)
ESLint found too many warnings (maximum: 0).

Silenced here with the same disable comment used elsewhere in the repo, only so this PR can be verified — probably worth landing on main directly. Worth noting testing.yml only runs on: [pull_request], so nothing catches this after a merge.

On pixi.js and TypeScript 7

Measured by installing published @pixi/ui next to pixi.js and compiling a consumer with skipLibCheck off:

pixi.js	TypeScript 7.0
8.6.2 (this repo's dev pin)	185 errors
8.20.1	183 errors
8.21.0+	clean

pixi.js v8.21.0 dropped the @webgpu/types reference that collided with the WebGPU types now built into TypeScript 7's lib.dom.d.ts. So pixi.js is not a blocker for TypeScript 7 consumers — but this repo develops against 8.6.2, sixteen minors behind. Updating that pin is a migration of its own (8.22.0 tightens Container.parent and maxWidth to nullable — six new strict-null errors — and breaks the jest transform), so it's deliberately left for a separate PR.

Verification

Full CI sequence on the merged branch, clean install:

Step	Result
npm run lint	pass
npm run types (5.x + 7.x)	pass
npm run test	pass
npm run docs	pass
npm run build	pass
npm run types:dist	pass — 18 exports entries

🤖 Generated with Claude Code

[CatchABus]

We can proceed with this but I'd treat it as a workaround solution until TS 7 is mature enough and the mentioned packages finally support it.