preview-in-playground-button-v3-example-composer-vite

Realistic example for the WordPress Playground v3 reusable preview workflows: a plugin that needs both composer install (PSR-4 autoload + a runtime dep) and npm run build (Vite-bundled admin JS) before it can run.

Demonstrates that the v3 reusable workflows handle a multi-toolchain build with no per-step boilerplate — caller setup is still ~20 lines across two files.

What's in here

• playground-demo-plugin.php — main plugin file. Loads vendor/autoload.php, calls into the namespaced PlaygroundDemo\Notice class.
• src/Notice.php — autoloaded class, uses a real Composer dep (psr/log) to prove composer install ran.
• composer.json — declares PSR-4 + a runtime require.
• src-js/admin.js + vite.config.js + package.json — Vite source and config, output goes to dist/admin.js (no hash, fixed name) so PHP can enqueue it without reading a manifest.
• .github/workflows/pr-preview-build.yml — runs composer install --no-dev, then npm install && npm run build, stages the result with rsync excludes, zips it.
• .github/workflows/pr-preview-publish.yml — exposes the zip, posts the preview button.

The reusable workflows are pinned to the in-development branch adamziel/build-command-reusable-workflows of WordPress/action-wp-playground-pr-preview. Repin to @v3 once that lands.