fix(build): do not copy polyfills to the dist OT unless building es5

[alicewriteswrongs]

Prior to this change Stencil will copy polyfills to the dist output target whether or not the user has indicated they'll be necessary.

The polyfills comprise two things: copying the polyfills themselves into the 'loader' path, and adding code to the lazy-loader entry points which loads those polyfills. Instead of just assuming that the user wants this, we now gate this behavior on whether buildEs5 is set on the Stencil configuration.

fixes #5416
STENCIL-1288

What is the current behavior?

Right now we copy a bunch of polyfills which won't be necessary outside of an ES5-only environment even when buildEs5 is not set. This adds some extra bulk to the dist build output.

See #5416 for more details.

What is the new behavior?

If the user has set buildEs5 to true then we copy the polyfills, otherwise we don't do anything.

Documentation

Does this introduce a breaking change?

• Yes
• No

Testing

The best way to test this is to build a sample stencil project with @stencil/core@latest and then with a version based on this build and then compare the output.

First do:

cd /tmp
npm init stencil@latest component test-no-polyfills
cd test-no-polyfills
npm install
npm run build

then edit .gitignore to remove dist/ and loader/ from the ignore. Then you can follow the setup steps in CONTRIBUTING.md for local dev (e.g. the tsconfig paths stuff).

Then if you check out this branch in your stencil repo locally and run npm link you should be able to use this script to test things out in your new stencil project:

#!/bin/bash

npm unlink @stencil/core

npm install @stencil/core@latest

npm run build

git add .

git commit -m "build with @stencil/core@latest"

npm link @stencil/core

npm run build

git add .

git commit -m "build with dev build"

save that to like test.sh or something in your little project, throw a chmod +x on there and you're good to go.

Then you can do

git diff $(git rev-parse @~)

to see the diff between the @stencil/core@latest build and the dev build

[github-actions]

--strictNullChecks error report

Typechecking with --strictNullChecks resulted in 1138 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/client-hydrate.ts	20
src/testing/puppeteer/puppeteer-element.ts	20
src/screenshot/connector-base.ts	19
src/runtime/vdom/vdom-render.ts	17
src/dev-server/request-handler.ts	15
src/compiler/prerender/prerender-optimize.ts	14
src/compiler/sys/stencil-sys.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/connected-callback.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
src/compiler/transpile/transpile-module.ts	12
src/mock-doc/test/attribute.spec.ts	12

Our most common errors

Typescript Error Code	Count
TS2322	361
TS2345	344
TS18048	205
TS18047	82
TS2722	37
TS2532	24
TS2531	21
TS2454	14
TS2790	11
TS2352	9
TS2769	8
TS2538	8
TS2416	7
TS2493	3
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	61	satisfies
src/compiler/types/validate-primary-package-output-target.ts	61	Record
src/testing/puppeteer/puppeteer-declarations.ts	485	WaitForEventOptions
src/compiler/sys/fetch/write-fetch-success.ts	7	writeFetchSuccessSync

[github-actions]

PR built and packed!

Download the tarball here: https://github.com/ionic-team/stencil/actions/runs/8986034283/artifacts/1480265747

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

unzip -d ~/Downloads ~/Downloads/stencil-core-4.18.0-dev.1715087629.688dc51.tgz.zip && npm install ~/Downloads/stencil-core-4.18.0-dev.1715087629.688dc51.tgz

[alicewriteswrongs]

noting two things

[alicewriteswrongs]

this is a little funny (the resolve call I mean) but I had to do this to get the tests passing on CI on Windows, you know, sometimes you gotta do what you gotta do

[alicewriteswrongs]

this is a new spec file, we didn't previously have coverage for this file in particular