Make protocol TypeScript declarations emittable in isolation

[kiftio]

What changes are you making?

Enable isolatedDeclarations for protocol/languages/typescript, so every exported value has a type that can be emitted file-by-file without cross-file inference. tsc --isolatedDeclarations reported five sites; this fixes them at the source:

• Generated catalog (generate_typescript_notifications.mjs): checkoutProtocolCatalogPayloadDecoders, notificationDescriptors and requestDescriptors get explicit named types (CheckoutProtocolCatalogPayloadDecoders, NotificationDescriptors, RequestDescriptors) in place of satisfies. The types are the same mapped types that were previously used for satisfies; the three new aliases are additive exports.
• EmbeddedCheckoutProtocol: explicit annotation using typeof queries instead of as const inference over shorthand properties.
• tsconfig: isolatedDeclarations: true (+ declaration: true, which it requires), so pnpm typecheck enforces this going forward.
• Codegen: the declaration-emit tsc call passes --isolatedDeclarations too, so regenerated .d.ts stay compliant.

The committed .d.ts files are regenerated: ProtocolNotifications.d.ts is 43 lines shorter (named mapped types instead of expanded object types) and embedded_checkout_protocol.d.ts uses typeof. Structurally identical: Checkout Kit Web's rolled-up dist/index.d.ts is byte-for-byte unchanged before and after, because API Extractor resolves the named types to the same shapes it produced before.

Why: this is the protocol-side half of the path recorded in #958. Four of the six config workarounds the rolldown-plugin-dts spike needed (generator: 'tsc', resolver: 'tsc', eager, isolatedDeclarations: false) existed only because the protocol package couldn't be emitted in isolation. With this in, a future swap to rolldown-plugin-dts needs essentially no workarounds — and the change is worth having regardless: isolated declarations make the package's types explicit and its declaration emit parallelisable. It doesn't do the swap; that remains a separate decision.

Stacked on #961 (Vite 8.3) so the eventual swap has both prerequisites in place.

How to test

cd protocol/languages/typescript && pnpm typecheck      # isolatedDeclarations on
cd protocol && pnpm test                                 # 88 tests incl. the generator
cd platforms/web && pnpm lint && pnpm test && pnpm build && pnpm verify && pnpm compare-snapshot
diff <(git show HEAD~1:… dist/index.d.ts) dist/index.d.ts   # empty

Validated: protocol typecheck with isolated declarations, 88 protocol tests, web lint / 337 unit / build / 9 built-package tests / snapshot, and the web index.d.ts diff is empty.

---

Before you merge

Important

• I've added tests to support my implementation (covered by isolatedDeclarations enforcement in typecheck and existing suites)
• I have read and agree with the Contribution Guidelines
• I have read and agree with the Code of Conduct
• I've updated the relevant platform README (not applicable)

[github-actions]

Bundle Size Budgets

Budget	Size	Limits	Result
Web JavaScript (uncompressed)	35.58 KiB (0 B)	35 KiB soft / 50 KiB hard	➖ Above budget; no increase
React Native npm package (gzip)	119.12 KiB (-513 B)	130 KiB soft / 150 KiB hard	✅ Within budget
Android AAR package (ZIP)	408.54 KiB (0 B)	450 KiB soft / 500 KiB hard	✅ Within budget

Bundle and package size

Web bundle sizes cover shipped runtime JavaScript. Package sizes cover the full published archive, including any source maps, declarations, and documentation it contains.

Platform	Measurement	Compression	Base	Head	Delta
Web	JavaScript bundle	Uncompressed	35.6 KiB	35.6 KiB	0 B
Web	JavaScript bundle	gzip	11.1 KiB	11.1 KiB	0 B
Web	npm package (.tgz)	gzip	99.1 KiB	99.2 KiB	+139 B
React Native	npm package (.tgz)	gzip	119.6 KiB	119.1 KiB	-513 B
Android	Library package (.aar)	ZIP	408.5 KiB	408.5 KiB	0 B

Web package files (uncompressed)

These are uncompressed file sizes; they do not sum to the compressed package size above.

File	Base	Head	Delta
dist/chunks/shopify-checkout.js.map	264.3 KiB	264.9 KiB	+572 B
dist/custom-elements.json	54.7 KiB	54.7 KiB	0 B
dist/index.d.ts	49.5 KiB	49.5 KiB	0 B
dist/chunks/shopify-checkout.js	35.2 KiB	35.2 KiB	0 B
README.md	24.5 KiB	24.5 KiB	0 B
package.json	3.9 KiB	3.9 KiB	0 B
LICENSE	1.1 KiB	1.1 KiB	0 B
dist/shopify-checkout.js.map	850 B	850 B	0 B
dist/index.js	255 B	255 B	0 B
dist/shopify-checkout.js	156 B	156 B	0 B
dist/shopify-checkout.d.ts	33 B	33 B	0 B

React Native package files (uncompressed)

These are uncompressed file sizes; they do not sum to the compressed package size above.

File	Base	Head	Delta
node_modules/@shopify/checkout-kit-protocol/src/generated/Models.ts	108.7 KiB	108.7 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/generated/Models.d.ts	73.1 KiB	73.1 KiB	0 B
android/src/main/java/com/shopify/reactnative/checkoutkit/ShopifyCheckoutKitModule.java	16.2 KiB	16.2 KiB	0 B
ios/ShopifyCheckoutKit.swift	16.1 KiB	16.1 KiB	0 B
ios/AcceleratedCheckoutButtons.swift	14.1 KiB	14.1 KiB	0 B
src/components/AcceleratedCheckoutButtons.tsx	13.0 KiB	13.0 KiB	0 B
src/index.ts	12.7 KiB	12.7 KiB	0 B
lib/commonjs/index.js	12.4 KiB	12.4 KiB	0 B
lib/commonjs/components/AcceleratedCheckoutButtons.js	11.4 KiB	11.4 KiB	0 B
src/index.d.ts	11.3 KiB	11.3 KiB	0 B
lib/commonjs/components/AcceleratedCheckoutButtons.js.map	10.4 KiB	10.4 KiB	0 B
lib/module/index.js	10.4 KiB	10.4 KiB	0 B
lib/module/components/AcceleratedCheckoutButtons.js	10.2 KiB	10.2 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/generated/ProtocolNotifications.ts	9.5 KiB	9.6 KiB	+185 B
lib/module/components/AcceleratedCheckoutButtons.js.map	9.1 KiB	9.1 KiB	0 B
lib/module/index.js.map	8.1 KiB	8.1 KiB	0 B
src/present-dispatcher.ts	8.0 KiB	8.0 KiB	0 B
lib/commonjs/index.js.map	7.9 KiB	7.9 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/generated/ProtocolRenameMap.ts	7.8 KiB	7.8 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/generated/ProtocolNotifications.d.ts	7.6 KiB	5.7 KiB	-1.9 KiB
…and 117 smaller files

Android package files (uncompressed)

These are uncompressed file sizes; they do not sum to the compressed package size above.

File	Base	Head	Delta
classes.jar	435.2 KiB	435.2 KiB	0 B
res/layout/checkout_view_content.xml	2.6 KiB	2.6 KiB	0 B
res/layout/checkout_sheet_content.xml	2.0 KiB	2.0 KiB	0 B
res/values/values.xml	1.3 KiB	1.3 KiB	0 B
R.txt	1.2 KiB	1.2 KiB	0 B
AndroidManifest.xml	922 B	922 B	0 B
proguard.txt	798 B	798 B	0 B
res/drawable/close.xml	431 B	431 B	0 B
res/menu/checkout_menu.xml	354 B	354 B	0 B
META-INF/com/android/build/gradle/aar-metadata.properties	157 B	157 B	0 B

How sizes are measured

Measured from the PR base SHA and PR head SHA. Web bundle rows sum shipped .js, .mjs, and .cjs files under dist/, excluding source maps and declarations. The gzip bundle size sums files compressed individually with gzip -n -9. npm package sizes are gzip-compressed .tgz archives; Android AAR sizes are ZIP archives. Package sizes are not final app binary sizes.

[github-actions]

Coverage Report

Status	Platform / target	Lines	Branches	Functions	Report
✅	Web	98.3%	86.86%	97.22%	Full report
✅	React Native	91.49%	87.3%	100%	Full report
✅	Embedded Checkout Protocol (TS)	94.05%	89.17%	90.91%	Full report

[github-actions]

Protocol — Coverage Report

Lines	Statements	Branches	Functions
	93.49% (158/169)	89.16% (107/120)	90.9% (30/33)

[github-actions]

React Native — Coverage Report

Lines	Statements	Branches	Functions
	90.97% (363/399)	87.29% (213/244)	100% (92/92)

[github-actions]

Web — Coverage Report

Lines	Statements	Branches	Functions
	95.62% (437/457)	86.86% (238/274)	97.22% (105/108)

[bitrise]

Bitrise builds

E2E · iOS CI

Install this build

Open Tophat, select your target device, then click Install. Links open on the Mac running Tophat.

SDK	Install
React Native	Install with Tophat
Swift	Install with Tophat
Kotlin	Install with Tophat

Checkout Kit E2E results

Status	Tags	Target	Platform	OS version tag	Device
✅	launch, checkout-presentation, checkout-completion, buyer-identity	react-native	ios	latest	iPhone 15 iOS 27 Beta
✅	launch, checkout-presentation, checkout-completion, buyer-identity	react-native	android	latest	Google Pixel 9 Android 17.0
✅	launch, checkout-presentation, checkout-completion, buyer-identity, preload	kotlin	android	latest	Google Pixel 9 Android 17.0
❌	launch, checkout-presentation, checkout-completion, buyer-identity, preload	swift	ios	latest	iPhone 15 iOS 27 Beta

Failures

Caution

If you believe an assertion is flaky, please raise a ticket in the #checkout-kit-devs channel so it can be addressed.

BrowserStack artifacts require BrowserStack access. Sign in to BrowserStack App Automate before opening artifact links.

iOS — swift

RuntimeError: BrowserStack build timed out: f1b90dd48099bd86bc9fcc3107ef30d7a6c7d186

Test	Status	Artifacts
—	❌	BrowserStack