Use TypeScript to check if a default case is required in `switch` #75854

eps1lon · 2025-02-10T10:30:55Z

Follow-up to https://github.com/vercel/next.js/pull/75839/files#r1948806062. TypeScript as switch exhaustiveness checks built in.

eps1lon · 2025-02-10T10:31:10Z

Use TypeScript to check if a default case is required in switch #75854 👈 (View in Graphite)
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eps1lon · 2025-02-10T10:34:34Z

...omponents/react-dev-overlay/_experimental/internal/container/runtime-error/use-error-hook.ts

@@ -21,17 +21,13 @@ export type SupportedErrorEvent = {

 function getErrorSignature(ev: SupportedErrorEvent): string {


Once the switch is not exhaustive, TypeScript will error here because that would change the return type to string | void.

ijjk · 2025-02-10T10:34:42Z

Failing test suites

Commit: 0eb587a

pnpm test test/integration/amp-export-validation/test/index.test.js (turbopack)

AMP Validation on Export > production mode > should have shown errors during build

Expand output

● AMP Validation on Export › production mode › should have shown errors during build

expect(received).toMatch(expected)

Expected pattern: /error.*The mandatory attribute 'height' is missing in tag 'amp-video'\./
Received string:  "   Loading config from /root/actions-runner/_work/next.js/next.js/test/integration/amp-export-validation/next.config.js
   Loading config from /root/actions-runner/_work/next.js/next.js/test/integration/amp-export-validation/next.config.js
   ▲ Next.js 15.2.0-canary.48 (Turbopack)·
   Checking validity of types ...
   Creating an optimized production build ...
   Loading config from /root/actions-runner/_work/next.js/next.js/test/integration/amp-export-validation/next.config.js
   Loading config from /root/actions-runner/_work/next.js/next.js/test/integration/amp-export-validation/next.config.js
   Building (0/7) ...
   Building (1/7)··
   Building (3/7)··
   Building (5/7)··
 ✓ Building (7/7)
 ✓ Compiled successfully in 2.3s
   Collecting page data ...
   Generating static pages (0/8) ...
   Generating static pages (2/8)··
 ⚠ Linting is disabled.
Error occurred prerendering page \"/cat\". Read more: https://nextjs.org/docs/messages/prerender-error
AssertionError: Assertion failed: WebAssembly is uninitialized

  at new module$contents$goog$asserts_AssertionError (../evalmachine.<anonymous>:106:1695)
  at module$contents$goog$asserts_doAssertFailure (../evalmachine.<anonymous>:107:354)
  at goog.asserts.assertExists (../evalmachine.<anonymous>:109:142)
  at Object.module$contents$amp$validator_validateString [as validateString] (../evalmachine.<anonymous>:2663:108)
  at Validator.validateString (../packages/next/dist/compiled/amphtml-validator/index.js:1:20650)
  at validateAmp (../packages/next/dist/export/routes/pages.js:87:34)
  at async exportPagesPage (../packages/next/dist/export/routes/pages.js:104:13)
  at async Span.traceAsyncFn (../packages/next/dist/trace/trace.js:156:20)
  at async exportPage (../packages/next/dist/export/worker.js:358:18)
  Export encountered an error on /cat, exiting the build.
   ⨯ Next.js build worker exited with code: 1 and signal: null
  "
  at Object.toMatch (integration/amp-export-validation/test/index.test.js:28:29)

Read more about building and testing Next.js in contributing.md.

ijjk · 2025-02-10T10:38:53Z

Stats from current PR

Default Build (Increase detected ⚠️)

General

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
buildDuration	20.1s	17s	N/A
buildDurationCached	16.1s	13.6s	N/A
nodeModulesSize	393 MB	393 MB	N/A
nextStartRea..uration (ms)	425ms	445ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
5306-HASH.js gzip	54.3 kB	54.3 kB	N/A
8276.HASH.js gzip	169 B	168 B	N/A
8377-HASH.js gzip	5.46 kB	5.46 kB	N/A
bccd1874-HASH.js gzip	53 kB	53 kB	✓
framework-HASH.js gzip	57.5 kB	57.5 kB	N/A
main-app-HASH.js gzip	246 B	245 B	N/A
main-HASH.js gzip	34.6 kB	34.5 kB	N/A
webpack-HASH.js gzip	1.71 kB	1.71 kB	N/A
Overall change	53 kB	53 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
polyfills-HASH.js gzip	39.4 kB	39.4 kB	✓
Overall change	39.4 kB	39.4 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
_app-HASH.js gzip	193 B	193 B	✓
_error-HASH.js gzip	193 B	193 B	✓
amp-HASH.js gzip	512 B	510 B	N/A
css-HASH.js gzip	343 B	342 B	N/A
dynamic-HASH.js gzip	1.84 kB	1.84 kB	✓
edge-ssr-HASH.js gzip	265 B	265 B	✓
head-HASH.js gzip	363 B	362 B	N/A
hooks-HASH.js gzip	393 B	392 B	N/A
image-HASH.js gzip	4.59 kB	4.58 kB	N/A
index-HASH.js gzip	268 B	268 B	✓
link-HASH.js gzip	2.35 kB	2.35 kB	N/A
routerDirect..HASH.js gzip	328 B	328 B	✓
script-HASH.js gzip	397 B	397 B	✓
withRouter-HASH.js gzip	323 B	326 B	N/A
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	3.59 kB	3.59 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
_buildManifest.js gzip	748 B	747 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
index.html gzip	523 B	524 B	N/A
link.html gzip	538 B	538 B	✓
withRouter.html gzip	519 B	521 B	N/A
Overall change	538 B	538 B	✓

Edge SSR bundle Size

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
edge-ssr.js gzip	130 kB	130 kB	N/A
page.js gzip	211 kB	211 kB	N/A
Overall change	0 B	0 B	✓

Middleware size

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
middleware-b..fest.js gzip	676 B	672 B	N/A
middleware-r..fest.js gzip	155 B	156 B	N/A
middleware.js gzip	31.3 kB	31.3 kB	N/A
edge-runtime..pack.js gzip	844 B	844 B	✓
Overall change	844 B	844 B	✓

Next Runtimes

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
app-page-exp...dev.js gzip	394 kB	394 kB	N/A
app-page-exp..prod.js gzip	132 kB	132 kB	✓
app-page-tur..prod.js gzip	145 kB	145 kB	✓
app-page-tur..prod.js gzip	141 kB	141 kB	✓
app-page.run...dev.js gzip	381 kB	381 kB	N/A
app-page.run..prod.js gzip	129 kB	129 kB	✓
app-route-ex...dev.js gzip	39.3 kB	39.3 kB	✓
app-route-ex..prod.js gzip	25.6 kB	25.6 kB	✓
app-route-tu..prod.js gzip	25.6 kB	25.6 kB	✓
app-route-tu..prod.js gzip	25.4 kB	25.4 kB	✓
app-route.ru...dev.js gzip	40.9 kB	40.9 kB	✓
app-route.ru..prod.js gzip	25.4 kB	25.4 kB	✓
dist_client_...dev.js gzip	356 B	356 B	✓
dist_client_...dev.js gzip	349 B	349 B	✓
pages-api-tu..prod.js gzip	9.69 kB	9.69 kB	✓
pages-api.ru...dev.js gzip	11.8 kB	11.8 kB	✓
pages-api.ru..prod.js gzip	9.68 kB	9.68 kB	✓
pages-turbo...prod.js gzip	21.9 kB	21.9 kB	✓
pages.runtim...dev.js gzip	31.5 kB	31.5 kB	✓
pages.runtim..prod.js gzip	21.9 kB	21.9 kB	✓
server.runti..prod.js gzip	60.7 kB	60.7 kB	✓
Overall change	897 kB	897 kB	✓

build cache Overall increase ⚠️

	vercel/next.js canary	vercel/next.js sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_	Change
0.pack gzip	2.11 MB	2.11 MB	N/A
index.pack gzip	76.3 kB	76.4 kB	⚠️ +129 B
Overall change	76.3 kB	76.4 kB	⚠️ +129 B

Diff details

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Diff for app-page-exp..ntime.dev.js

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Diff for app-page.runtime.dev.js

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Commit: 0eb587a

Use TypeScript to check if a default case is required in switch

0eb587a

ijjk added created-by: Next.js team PRs by the Next.js team. type: next labels Feb 10, 2025

eps1lon mentioned this pull request Feb 10, 2025

[error overlay] missing html tags error should be blocking #75839

Merged

eps1lon commented Feb 10, 2025

View reviewed changes

huozhi approved these changes Feb 10, 2025

View reviewed changes

eps1lon marked this pull request as ready for review February 10, 2025 11:34

eps1lon enabled auto-merge (squash) February 10, 2025 11:37

eps1lon merged commit 8efcdbe into canary Feb 10, 2025
131 checks passed

eps1lon deleted the sebbie/02-10-use_typescript_to_check_if_a_default_case_is_required_in_switch_ branch February 10, 2025 11:40

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Use TypeScript to check if a default case is required in `switch` #75854

Use TypeScript to check if a default case is required in `switch` #75854

eps1lon commented Feb 10, 2025 •

edited

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eps1lon commented Feb 10, 2025

eps1lon Feb 10, 2025

ijjk commented Feb 10, 2025

ijjk commented Feb 10, 2025

		@@ -21,17 +21,13 @@ export type SupportedErrorEvent = {

		function getErrorSignature(ev: SupportedErrorEvent): string {

Use TypeScript to check if a default case is required in switch #75854

Use TypeScript to check if a default case is required in switch #75854

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eps1lon commented Feb 10, 2025 • edited Loading

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ijjk commented Feb 10, 2025

Failing test suites

ijjk commented Feb 10, 2025

Stats from current PR

Use TypeScript to check if a default case is required in `switch` #75854

Use TypeScript to check if a default case is required in `switch` #75854

eps1lon commented Feb 10, 2025 •

edited

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