···11+# Svelte + TS + Vite
22+33+This template should help get you started developing with Svelte and TypeScript in Vite.
44+55+## Recommended IDE Setup
66+77+[VS Code](https://code.visualstudio.com/) + [Svelte](https://marketplace.visualstudio.com/items?itemName=svelte.svelte-vscode).
88+99+## Need an official Svelte framework?
1010+1111+Check out [SvelteKit](https://github.com/sveltejs/kit#readme), which is also powered by Vite. Deploy anywhere with its serverless-first approach and adapt to various platforms, with out of the box support for TypeScript, SCSS, and Less, and easily-added support for mdsvex, GraphQL, PostCSS, Tailwind CSS, and more.
1212+1313+## Technical considerations
1414+1515+**Why use this over SvelteKit?**
1616+1717+- It brings its own routing solution which might not be preferable for some users.
1818+- It is first and foremost a framework that just happens to use Vite under the hood, not a Vite app.
1919+2020+This template contains as little as possible to get started with Vite + TypeScript + Svelte, while taking into account the developer experience with regards to HMR and intellisense. It demonstrates capabilities on par with the other `create-vite` templates and is a good starting point for beginners dipping their toes into a Vite + Svelte project.
2121+2222+Should you later need the extended capabilities and extensibility provided by SvelteKit, the template has been structured similarly to SvelteKit so that it is easy to migrate.
2323+2424+**Why `global.d.ts` instead of `compilerOptions.types` inside `jsconfig.json` or `tsconfig.json`?**
2525+2626+Setting `compilerOptions.types` shuts out all other types not explicitly listed in the configuration. Using triple-slash references keeps the default TypeScript setting of accepting type information from the entire workspace, while also adding `svelte` and `vite/client` type information.
2727+2828+**Why include `.vscode/extensions.json`?**
2929+3030+Other templates indirectly recommend extensions via the README, but this file allows VS Code to prompt the user to install the recommended extension upon opening the project.
3131+3232+**Why enable `allowJs` in the TS template?**
3333+3434+While `allowJs: false` would indeed prevent the use of `.js` files in the project, it does not prevent the use of JavaScript syntax in `.svelte` files. In addition, it would force `checkJs: false`, bringing the worst of both worlds: not being able to guarantee the entire codebase is TypeScript, and also having worse typechecking for the existing JavaScript. In addition, there are valid use cases in which a mixed codebase may be relevant.
3535+3636+**Why is HMR not preserving my local component state?**
3737+3838+HMR state preservation comes with a number of gotchas! It has been disabled by default in both `svelte-hmr` and `@sveltejs/vite-plugin-svelte` due to its often surprising behavior. You can read the details [here](https://github.com/rixo/svelte-hmr#svelte-hmr).
3939+4040+If you have state that's important to retain within a component, consider creating an external store which would not be replaced by HMR.
4141+4242+```ts
4343+// store.ts
4444+// An extremely simple external store
4545+import { writable } from 'svelte/store'
4646+export default writable(0)
4747+```
···11+import { vitePreprocess } from '@sveltejs/vite-plugin-svelte'
22+33+export default {
44+ // Consult https://svelte.dev/docs#compile-time-svelte-preprocess
55+ // for more information about preprocessors
66+ preprocess: vitePreprocess(),
77+}
+20
web/tsconfig.app.json
···11+{
22+ "extends": "@tsconfig/svelte/tsconfig.json",
33+ "compilerOptions": {
44+ "target": "ESNext",
55+ "useDefineForClassFields": true,
66+ "module": "ESNext",
77+ "resolveJsonModule": true,
88+ /**
99+ * Typecheck JS in `.svelte` and `.js` files by default.
1010+ * Disable checkJs if you'd like to use dynamic types in JS.
1111+ * Note that setting allowJs false does not prevent the use
1212+ * of JS in `.svelte` files.
1313+ */
1414+ "allowJs": true,
1515+ "checkJs": true,
1616+ "isolatedModules": true,
1717+ "moduleDetection": "force"
1818+ },
1919+ "include": ["src/**/*.ts", "src/**/*.js", "src/**/*.svelte"]
2020+}