NXT-573: Added Vite Plugin

[daniel-stoian-lgp]

Checklist

• I have read and understand the contribution guide
• A CHANGELOG entry is included
• At least one test case is included for this feature or bug fix
• Documentation was added or is not needed
• This is an API breaking change

Issue Resolved / Feature Added

Adds support for Vite migration (NXT-573): the Vite/Rollup counterparts of the existing webpack plugins and mixins, so @enact/cli can build and serve Enact apps with Vite.

Must land with (or before) the companion @enact/cli PR — cli's config/vite.config.js consumes ViteHtmlPlugin / ViteILibPlugin / ViteWebOSMetaPlugin from this package. The CLI PR fails without it.

New — Vite/Rollup plugins (mirroring where the webpack plugins already live):

New	webpack counterpart	Purpose
plugins/ViteHtmlPlugin	HtmlWebpackPlugin + .ejs	Renders the same HTML template (Enact apps ship no index.html); serves in dev, emits index.html in build.
plugins/ViteILibPlugin	ILibPlugin	Defines the ILIB_* constants (build and the dev dep-optimizer) and copies/serves the iLib + resources/ data. Adds locale filtering via a locales option.
plugins/ViteWebOSMetaPlugin	WebOSMetaPlugin	Emits/serves appinfo.json + icons + localized appinfo, incl. $-prefixed sys-assets; supplies the <title> fallback.

New mixins (Vite counterparts to the webpack mixins):

• mixins/vite.js : build-shaping flags (--no-minify, --verbose, --stats), exposed as mixins.applyVite.
• mixins/vite-framework.js: --framework / --externals via a shared ESM bundle + import map (the analog of webpack's DLL + manifest), incl. theme-repo self-inclusion and --externals-polyfill.
• mixins/vite-isomorphic.js: --isomorphic: a real vite build --ssr + per-locale prerender + assembly into the webpack-compatible output (fallback index.html + deduped index.<variant>.html + locale-map.json + per-locale appinfo).
• mixins/vite-snapshot.js: --snapshot: self-contained UMD bundle (App global) + mksnapshot invocation + appinfo.json v8SnapshotFile tagging.
• plugins/SnapshotPlugin/snapshot-helper-esm.js + snapshot-mock.js: ESM re-implementations of the CJS snapshot helpers. Needed because Rollup hoists CJS requires, so the original helper's in-line ordering (mock window installed before react-dom/client) cannot be reproduced; import order makes it deterministic. Reuses the bundler-agnostic mock-window.js + @enact/core/snapshot.

Refactors that touch the existing webpack path : these are the parts worth review attention. Each extracts logic that both bundlers now need into a shared, dependency-free module, with no intended behavior change to webpack:

Extracted to	From	Now shared with
plugins/ILibPlugin/ilib-paths.js	ILibPlugin/index.js (packageSearch, transformPath, bundleConst)	ViteILibPlugin
plugins/PrerenderPlugin/parse-locales.js	PrerenderPlugin/index.js (parseLocales, detectLocales)	ViteILibPlugin, cli's pack.js
plugins/WebOSMetaPlugin/appinfo.js	WebOSMetaPlugin/index.js (props, readAppInfo, rootAppInfo)	ViteWebOSMetaPlugin
mixins/framework-libraries.js	mixins/framework.js, mixins/externals.js (the react library list, non-runtime @enact package list)	mixins/vite-framework.js

Also: index.js exports the three new plugins; mixins/index.js gains applyVite (the webpack apply can't be reused: it mutates webpack-specific config).

Resolution

The Vite path is validated end-to-end against real apps (Sandstone/React 18 and Limestone/React 19, which ships raw @enact source), including a real browser render.

Why this shape: @enact/i18n's runtime loader, the prerender templates, FileXHR, and mock-window.js are all already bundler-agnostic, so the Vite plugins reuse them rather than reimplementing. The webpack-only pieces that had no equivalent (GracefulFsPlugin) are not migrated.

Additional Considerations

Links

NXT-573

Comments

Enact-DCO-1.0-Signed-off-by: Daniel Stoian (daniel.stoian@lgepartner.com)