plugins VS Svelte

But when I start a production bundling + build process, which I guess is actually made with rollup, I see Unexpected token (Note that you need plugins to import files that are not JavaScript). Lookin around, it seems like this is a rollup error, not a vite error.

rollup v3.2.3 bundles ./src/index.js → dist/bundle.js... babelHelpers: 'bundled' option was used by default. It is recommended to configure this option explicitly, read more here: https://github.com/rollup/plugins/tree/master/packages/babel#babelhelpers [!] (plugin commonjs--resolver) SyntaxError: Unexpected token (12:2) in /Users/krishna404/codeProjects/All_SmartAgent/desktopSmartAgent/src/index.js src/index.js (12:2) 10: import { AdapterDateFns } from '@mui/x-date-pickers/AdapterDateFns'; 11: ReactDOM.render( 12: ^ 13:

Next, we need to tell Rollup which of the modules used in our code are external to our library. Together with @rollup/plugin-node-resolve, this ensures that Rollup doesn't bundle those dependencies into our final bundle. The function makeExternalPredicate() generates the list of package names specified in dependencies and peerDependencies in package.json. All credit for this and a big thank you goes out to Mateusz Burzyński for providing it in this issue:

// If you have external dependencies installed from // npm, you'll most likely need these plugins. In // some cases you'll need additional configuration - // consult the documentation for details: // https://github.com/rollup/plugins/tree/master/packages/commonjs resolve({ browser: true, dedupe: ['svelte'], }), commonjs(), // In dev mode, call `npm run start` once // the bundle has been generated !production && serve(), // Watch the `public` directory and refresh the // browser on changes when not in production !production && livereload('public'), // If we're building for production (npm run build // instead of npm run dev), minify production && terser(), ], watch: { clearScreen: false, },

Then in this case, if you don't want to use Vite's dynamic imports, you can conditionally use this plugin in your vite config under rollupOptions. https://github.com/rollup/plugins/tree/master/packages/inject. This way you won't even need to use env vars.

compilerOptions: { // enable run-time checks when not in production dev: !production } }), // we'll extract any component CSS out into // a separate file - better for performance css({ output: 'bundle.css' }), // If you have external dependencies installed from // npm, you'll most likely need these plugins. In // some cases you'll need additional configuration - // consult the documentation for details: // https://github.com/rollup/plugins/tree/master/packages/commonjs resolve({ browser: true, dedupe: ['svelte'] }), commonjs(), // In dev mode, call \npm run start` once // the bundle has been generated !production && serve(), // Watch the `public` directory and refresh the // browser on changes when not in production !production && livereload('public'), // If we're building for production (npm run build // instead of npm run dev), minify production && terser() ], watch: { clearScreen: false } };`

You should submit an issue there: https://github.com/rollup/plugins/tree/master/packages/commonjs

In Webpack 5, this is (surprisingly) simple to setup. Parcel 2 handles this out of the box with a special import prefix. Rollup has an official plugin.

The only workaround to have an isomorphic __dirname or __filename to be used for both "cjs" and "esm" without using build-time tools like @rollup/plugin-replace or esbuild "define" would be using a library like filedirname that does a trick inspecting error stacks, it's clearly not the cleanest solution.

import svelte from 'rollup-plugin-svelte'; import commonjs from '@rollup/plugin-commonjs'; import resolve from '@rollup/plugin-node-resolve'; import livereload from 'rollup-plugin-livereload'; import { terser } from 'rollup-plugin-terser'; import css from 'rollup-plugin-css-only'; import sveltePreprocess from 'svelte-preprocess'; const production = !process.env.ROLLUP_WATCH; function serve() { let server; function toExit() { if (server) server.kill(0); } return { writeBundle() { if (server) return; server = require('child_process').spawn( 'npm', ['run', 'start', '--', '--dev'], { stdio: ['ignore', 'inherit', 'inherit'], shell: true, } ); process.on('SIGTERM', toExit); process.on('exit', toExit); }, }; } export default { input: 'src/main.js', output: { sourcemap: true, format: 'iife', name: 'app', file: 'public/build/bundle.js', }, plugins: [ svelte({ preprocess: sveltePreprocess({ sourceMap: !production, postcss: { plugins: [require('tailwindcss'), require('autoprefixer')], }, }), compilerOptions: { // enable run-time checks when not in production dev: !production, }, }), // we'll extract any component CSS out into // a separate file - better for performance css({ output: 'bundle.css' }), // If you have external dependencies installed from // npm, you'll most likely need these plugins. In // some cases you'll need additional configuration - // consult the documentation for details: // https://github.com/rollup/plugins/tree/master/packages/commonjs resolve({ browser: true, dedupe: ['svelte'], }), commonjs(), // In dev mode, call `npm run start` once // the bundle has been generated !production && serve(), // Watch the `public` directory and refresh the // browser on changes when not in production !production && livereload('public'), // If we're building for production (npm run build // instead of npm run dev), minify production && terser(), ], watch: { clearScreen: false, }, };

React has introduced measures like batching state updates, background concurrent rendering and memoization to tackle this. My opinion is that the best way to solve the problem is by improving their reactivity model. The app needs to be able to track the code that should be re-run on updating a given state variable and specifically update the UI corresponding to this update. Tools like solid.js and svelte work in this manner. It also eliminates the need for a virtual DOM and diffing.

Similarly to Promises/A+, this effort focuses on aligning the JavaScript ecosystem. If this alignment is successful, then a standard could emerge, based on that experience. Several framework authors are collaborating here on a common model which could back their reactivity core. The current draft is based on design input from the authors/maintainers of Angular, Bubble, Ember, FAST, MobX, Preact, Qwik, RxJS, Solid, Starbeam, Svelte, Vue, Wiz, and more…

Svelte is a powerful web framework that offers a fresh approach to building web applications. Its simplicity, reactivity model, and built-in features make it an excellent choice for developers looking to create efficient and maintainable applications. By following this guide, you should now have a good understanding of how to get started with Svelte and build your first components, routes, and transitions. You can read more about svelte on the official Svelte website.

Use .NET features (especially dotnet watch) as a setup for a client-side Svelte application, starting from a simple C# console app.

Volar originally was Vue3's language support tool for VScode (I don't know about other editors). By today, volar has become a language indipendent framework to create language tools. It might still be a bit early for the dev with skill issues like me to use it and build some tools, but astro and svelte already use Volar to create their language tools.