fix(compiler): removed support for tagNameTransform

[christian-bromann]

What is the current behavior?

It seems like Stencil currently allows to transform the tag name at runtime. The feature was introduced in https://github.com/ionic-team/stencil/pull/2343/files but was never really introduced nor added to the docs.

What is the new behavior?

I suggest to remove this entirely since we don't have any tests for this nor do we know how it suppose to behave.

Documentation

Does this introduce a breaking change?

• Yes
• No

Technically yes but since we never documented it, it was never actually been released as a feature.

Testing

Other information

n/a

[github-actions]

PR built and packed!

Download the tarball here: https://github.com/ionic-team/stencil/actions/runs/9651629167/artifacts/1633239046

If your browser saves files to ~/Downloads you can install it like so:

unzip -d ~/Downloads ~/Downloads/stencil-core-4.18.3-dev.1719259258.093e4de.tgz.zip && npm install ~/Downloads/stencil-core-4.18.3-dev.1719259258.093e4de.tgz

[github-actions]

@stencil/core@4.19.2 ts
tsc --noEmit --project scripts/tsconfig.json && tsx scripts/tech-debt-burndown-report.ts

--strictNullChecks error report

Typechecking with --strictNullChecks resulted in 1068 errors on this branch.

That's the same number of errors on main, so at least we're not creating new ones!

reports and statistics

Our most error-prone files

Path	Error Count
src/dev-server/index.ts	37
src/dev-server/server-process.ts	32
src/compiler/prerender/prerender-main.ts	22
src/runtime/vdom/vdom-render.ts	22
src/runtime/client-hydrate.ts	20
src/runtime/vdom/test/patch.spec.ts	19
src/runtime/vdom/test/util.spec.ts	19
src/screenshot/connector-base.ts	19
src/testing/puppeteer/puppeteer-element.ts	19
src/dev-server/request-handler.ts	15
src/compiler/prerender/prerender-optimize.ts	14
src/compiler/sys/stencil-sys.ts	14
src/runtime/connected-callback.ts	14
src/sys/node/node-sys.ts	14
src/compiler/prerender/prerender-queue.ts	13
src/compiler/sys/in-memory-fs.ts	13
src/runtime/set-value.ts	13
src/compiler/output-targets/output-www.ts	12
src/compiler/transformers/test/parse-vdom.spec.ts	12
src/compiler/transformers/transform-utils.ts	12

Our most common errors

Typescript Error Code	Count
TS2322	338
TS2345	326
TS18048	188
TS18047	99
TS2722	27
TS2531	19
TS2532	18
TS2790	11
TS2454	10
TS2352	9
TS2769	8
TS2416	7
TS2538	4
TS18046	2
TS2684	1
TS2430	1

Unused exports report

There are 15 unused exports on this PR. That's the same number of errors on main, so at least we're not creating new ones!

Unused exports

File	Line	Identifier
src/runtime/bootstrap-lazy.ts	21	setNonce
src/screenshot/screenshot-fs.ts	18	readScreenshotData
src/testing/testing-utils.ts	198	withSilentWarn
src/utils/index.ts	145	CUSTOM
src/utils/index.ts	245	NODE_TYPES
src/utils/index.ts	269	normalize
src/utils/index.ts	7	escapeRegExpSpecialCharacters
src/compiler/app-core/app-data.ts	25	BUILD
src/compiler/app-core/app-data.ts	115	Env
src/compiler/app-core/app-data.ts	117	NAMESPACE
src/compiler/fs-watch/fs-watch-rebuild.ts	123	updateCacheFromRebuild
src/compiler/types/validate-primary-package-output-target.ts	82	satisfies
src/compiler/types/validate-primary-package-output-target.ts	82	Record
src/testing/puppeteer/puppeteer-declarations.ts	496	WaitForEventOptions
src/compiler/sys/fetch/write-fetch-success.ts	7	writeFetchSuccessSync

[johnjenkins]

Hi!
just to make it known this feature is definitely used by the community https://dev.to/sanderand/running-multiple-versions-of-a-stencil-design-system-without-conflicts-2f46 :)

[TRMW]

Also wanted to chime in and say my team is currently using this feature!

[christian-bromann]

@johnjenkins @TRMW thanks for providing feedback. Mind sharing in what context you are using this? What is the problem you are trying to solve?

[johnjenkins]

I believe, essentially, the use cases are outlined by scoped custom element registries so if stencil can work with that proposal / polyfill then that’d be an alternative / better way forward

[ryuran]

I confirm, we also use it and struggle with angular react output target.

[TRMW]

We are also using it as an alternative to scoped custom element registries. We use Stencil for a design system component library, and there are sometimes times when multiple versions of that library end up on the same page. We use this to allow teams to prefix/suffix their custom element names to ensure they always get the version they expect.

[christian-bromann]

Closing as we plan to use this feature to support scoped components.