feat: include server assets for Vercel serverless functions

.changeset/loud-needles-refuse.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-vercel': minor
+---
+
+feat: bundle server assets with serverless functions

.changeset/selfish-bobcats-run.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': minor
+---
+
+feat: adapter method to get server assets used by each route

documentation/docs/25-build-and-deploy/80-adapter-netlify.md

@@ -107,8 +107,29 @@ Additionally, you can add your own Netlify functions by creating a directory for
 	directory = "functions"
 ```
 
-## Troubleshooting
-
 ### Accessing the file system
 
-You can't access the file system through methods like `fs.readFileSync` in Serverless/Edge environments. If you need to access files that way, do that during building the app through [prerendering](https://kit.svelte.dev/docs/page-options#prerender). If you have a blog for example and don't want to manage your content through a CMS, then you need to prerender the content (or prerender the endpoint from which you get it) and redeploy your blog everytime you add new content.
+You can [use files in Netlify Serverless Functions](https://www.netlify.com/blog/2021/08/12/how-to-include-files-in-netlify-serverless-functions/).
+
+```js
+// @errors: 2307 7031
+/// file: +server.js
+import fs from "node:fs";
+import path from "node:path";
+import { dev } from '$app/environment';
+
+// importing a static asset will return the resolved path in the production build
+import PalatinoBoldFont from "$lib/fonts/PalatinoBold.ttf";
+
+const cwd = process.cwd();
+
+// server assets live in `.netlify/server` when deployed to Netlify
+const dir = dev ? cwd : path.join(cwd, '.netlify/server');
+
+const pathToFile = path.join(dir, PalatinoBoldFont);
+
+export async function GET() {
+  const file = fs.readFileSync(pathToFile);
+	// ...
+}
+```

documentation/docs/25-build-and-deploy/90-adapter-vercel.md

@@ -153,8 +153,25 @@ If you have Vercel functions contained in the `api` directory at the project's r
 
 Projects created before a certain date may default to using an older Node version than what SvelteKit currently requires. You can [change the Node version in your project settings](https://vercel.com/docs/concepts/functions/serverless-functions/runtimes/node-js#node.js-version).
 
-## Troubleshooting
-
 ### Accessing the file system
 
-You can't access the file system through methods like `fs.readFileSync` in Serverless/Edge environments. If you need to access files that way, do that during building the app through [prerendering](https://kit.svelte.dev/docs/page-options#prerender). If you have a blog for example and don't want to manage your content through a CMS, then you need to prerender the content (or prerender the endpoint from which you get it) and redeploy your blog everytime you add new content.
+You can [use files in Serverless Functions on Vercel](https://vercel.com/guides/how-can-i-use-files-in-serverless-functions).
+
+```js
+// @errors: 2307 7031
+/// file: api/pdf/+server.js
+import fs from "node:fs";
+import path from "node:path";
+
+// importing a static asset will return the resolved path in the production build
+import PalatinoBoldFont from "$lib/fonts/PalatinoBold.ttf";
+
+const pathToFile = path.join(process.cwd(), PalatinoBoldFont);
+
+export async function GET() {
+	const file = fs.readFileSync(pathToFile);
+	// ...
+}
+```
+
+> Only assets that are imported in `+page.server`, `+layout.server` and `+server` files are included in the Serverless Function bundle.

packages/adapter-vercel/.gitignore

@@ -1,2 +1,3 @@
 .DS_Store
 node_modules
+.vercel

packages/adapter-vercel/index.js

@@ -59,8 +59,8 @@ const plugin = function (defaults = {}) {
 
 			/**
 			 * @param {string} name
-			 * @param {import('.').ServerlessConfig} config
-			 * @param {import('@sveltejs/kit').RouteDefinition<import('.').Config>[]} routes
+			 * @param {import('./index.js').ServerlessConfig} config
+			 * @param {import('@sveltejs/kit').RouteDefinition<import('./index.js').Config>[]} routes
 			 */
 			async function generate_serverless_function(name, config, routes) {
 				const relativePath = path.posix.relative(tmp, builder.getServerDirectory());
@@ -81,14 +81,15 @@ const plugin = function (defaults = {}) {
 					builder,
 					`${tmp}/index.js`,
 					`${dirs.functions}/${name}.func`,
-					config
+					config,
+					routes
 				);
 			}
 
 			/**
 			 * @param {string} name
-			 * @param {import('.').EdgeConfig} config
-			 * @param {import('@sveltejs/kit').RouteDefinition<import('.').EdgeConfig>[]} routes
+			 * @param {import('./index.js').EdgeConfig} config
+			 * @param {import('@sveltejs/kit').RouteDefinition<import('./index.js').EdgeConfig>[]} routes
 			 */
 			async function generate_edge_function(name, config, routes) {
 				const tmp = builder.getBuildDirectory(`vercel-tmp/${name}`);
@@ -135,7 +136,7 @@ const plugin = function (defaults = {}) {
 				);
 			}
 
-			/** @type {Map<string, { i: number, config: import('.').Config, routes: import('@sveltejs/kit').RouteDefinition<import('.').Config>[] }>} */
+			/** @type {Map<string, { i: number, config: import('./index.js').Config, routes: import('@sveltejs/kit').RouteDefinition<import('./index.js').Config>[] }>} */
 			const groups = new Map();
 
 			/** @type {Map<string, { hash: string, route_id: string }>} */
@@ -144,7 +145,7 @@ const plugin = function (defaults = {}) {
 			/** @type {Map<string, string>} */
 			const functions = new Map();
 
-			/** @type {Map<import('@sveltejs/kit').RouteDefinition<import('.').Config>, { expiration: number | false, bypassToken: string | undefined, allowQuery: string[], group: number, passQuery: true }>} */
+			/** @type {Map<import('@sveltejs/kit').RouteDefinition<import('./index.js').Config>, { expiration: number | false, bypassToken: string | undefined, allowQuery: string[], group: number, passQuery: true }>} */
 			const isr_config = new Map();
 
 			/** @type {Set<string>} */
@@ -163,7 +164,7 @@ const plugin = function (defaults = {}) {
 				}
 
 				const node_runtime = /nodejs([0-9]+)\.x/.exec(runtime);
-				if (runtime !== 'edge' && (!node_runtime || node_runtime[1] < 18)) {
+				if (runtime !== 'edge' && (!node_runtime || +node_runtime[1] < 18)) {
 					throw new Error(
 						`Invalid runtime '${runtime}' for route ${route.id}. Valid runtimes are 'edge' and 'nodejs18.x' or higher ` +
 							'(see the Node.js Version section in your Vercel project settings for info on the currently supported versions).'
@@ -368,7 +369,7 @@ function write(file, data) {
 // This function is duplicated in adapter-static
 /**
  * @param {import('@sveltejs/kit').Builder} builder
- * @param {import('.').Config} config
+ * @param {import('index.js').Config} config
  */
 function static_vercel_config(builder, config) {
 	/** @type {any[]} */
@@ -377,8 +378,11 @@ function static_vercel_config(builder, config) {
 	/** @type {Record<string, { path: string }>} */
 	const overrides = {};
 
-	/** @type {import('./index').ImagesConfig} */
-	const images = config.images;
+	/** @type {import('./index.js').ImagesConfig | undefined} */
+	let images;
+	if (config.runtime !== 'edge') {
+		images = /** @type {import('./index.js').ServerlessConfig} */ (config).images;
+	}
 
 	for (const [src, redirect] of builder.prerendered.redirects) {
 		prerendered_redirects.push({
@@ -434,9 +438,10 @@ function static_vercel_config(builder, config) {
  * @param {import('@sveltejs/kit').Builder} builder
  * @param {string} entry
  * @param {string} dir
- * @param {import('.').ServerlessConfig} config
+ * @param {import('./index.js').ServerlessConfig} config
+ * @param {import('@sveltejs/kit').RouteDefinition[]} routes
  */
-async function create_function_bundle(builder, entry, dir, config) {
+async function create_function_bundle(builder, entry, dir, config, routes) {
 	fs.rmSync(dir, { force: true, recursive: true });
 
 	let base = entry;
@@ -544,6 +549,24 @@ async function create_function_bundle(builder, entry, dir, config) {
 		)
 	);
 
+	const server_assets = builder.getServerAssets();
+	let routes_assets = new Set(server_assets.rootErrorPage);
+
+	for (const route of routes) {
+		const assets = server_assets.routes.get(route.id);
+		if (assets) {
+			routes_assets = new Set([...routes_assets, ...assets]);
+		}
+	}
+
+	if (server_assets.hooks) {
+		routes_assets = new Set([...routes_assets, ...server_assets.hooks]);
+	}
+
+	for (const asset of routes_assets) {
+		builder.copy(path.join(builder.getServerDirectory(), asset), path.join(dir, asset));
+	}
+
 	write(`${dir}/package.json`, JSON.stringify({ type: 'module' }));
 }
 

packages/adapter-vercel/package.json

@@ -28,13 +28,14 @@
 		"lint": "prettier --check .",
 		"format": "pnpm lint --write",
 		"check": "tsc",
-		"test": "vitest run"
+		"test": "vitest run & pnpm -r --workspace-concurrency 1 --filter=\"./test/**\" test"
 	},
 	"dependencies": {
 		"@vercel/nft": "^0.26.1",
 		"esbuild": "^0.19.9"
 	},
 	"devDependencies": {
+		"@playwright/test": "1.30.0",
 		"@sveltejs/kit": "workspace:^",
 		"@sveltejs/vite-plugin-svelte": "^3.0.1",
 		"@types/node": "^18.19.3",

packages/adapter-vercel/test/apps/split/.gitignore

@@ -0,0 +1,10 @@
+.DS_Store
+node_modules
+/build
+/.svelte-kit
+/package
+.env
+.env.*
+!.env.example
+vite.config.js.timestamp-*
+vite.config.ts.timestamp-*

packages/adapter-vercel/test/apps/split/.npmrc

@@ -0,0 +1 @@
+engine-strict=true

packages/adapter-vercel/test/apps/split/package.json

@@ -0,0 +1,18 @@
+{
+	"name": "~TODO~",
+	"version": "0.0.1",
+	"private": true,
+	"scripts": {
+		"dev": "vite dev",
+		"build": "vite build",
+		"preview": "vite preview",
+		"test": "playwright test"
+	},
+	"devDependencies": {
+		"@sveltejs/kit": "workspace:^",
+		"svelte": "^4.2.8",
+		"typescript": "^5.3.3",
+		"vite": "^5.0.8"
+	},
+	"type": "module"
+}

packages/adapter-vercel/test/apps/split/playwright.config.js

@@ -0,0 +1 @@
+export { config as default } from '../../utils.js';

packages/adapter-vercel/test/apps/split/src/app.d.ts

@@ -0,0 +1,12 @@
+// See https://kit.svelte.dev/docs/types#app
+// for information about these interfaces
+declare global {
+	namespace App {
+		// interface Error {}
+		// interface Locals {}
+		// interface PageData {}
+		// interface Platform {}
+	}
+}
+
+export {};

packages/adapter-vercel/test/apps/split/src/app.html

@@ -0,0 +1,12 @@
+<!doctype html>
+<html lang="en">
+	<head>
+		<meta charset="utf-8" />
+		<link rel="icon" href="%sveltekit.assets%/favicon.png" />
+		<meta name="viewport" content="width=device-width, initial-scale=1" />
+		%sveltekit.head%
+	</head>
+	<body data-sveltekit-preload-data="hover">
+		<div style="display: contents">%sveltekit.body%</div>
+	</body>
+</html>

packages/adapter-vercel/test/apps/split/src/hooks.server.js

@@ -0,0 +1,6 @@
+import text from '$lib/hooks.server.js.txt';
+
+export async function handle({ event, resolve }) {
+	event.setHeaders({ 'x-server-asset': text });
+	return resolve(event);
+}

packages/adapter-vercel/test/apps/split/src/lib/+error.svelte.txt

@@ -0,0 +1 @@
++error.svelte

packages/adapter-vercel/test/apps/split/src/lib/+layout.js.txt

@@ -0,0 +1 @@
++layout.js

packages/adapter-vercel/test/apps/split/src/lib/+layout.server.js.txt

@@ -0,0 +1 @@
++layout.server.js

packages/adapter-vercel/test/apps/split/src/lib/+layout.svelte.txt

@@ -0,0 +1 @@
++layout.svelte

packages/adapter-vercel/test/apps/split/src/lib/+page.js.txt

@@ -0,0 +1 @@
++page.js

packages/adapter-vercel/test/apps/split/src/lib/+page.server.js.txt

@@ -0,0 +1 @@
++page.server.js

packages/adapter-vercel/test/apps/split/src/lib/+page.svelte.txt

@@ -0,0 +1 @@
++page.svelte

packages/adapter-vercel/test/apps/split/src/lib/+server.js.txt

@@ -0,0 +1 @@
++server.js

packages/adapter-vercel/test/apps/split/src/lib/hooks.server.js.txt

@@ -0,0 +1 @@
+hooks.server.js

packages/adapter-vercel/test/apps/split/src/lib/root_error.txt

@@ -0,0 +1 @@
+root_error

packages/adapter-vercel/test/apps/split/src/lib/root_layout.txt

@@ -0,0 +1 @@
+root_layout

packages/adapter-vercel/test/apps/split/src/lib/transitive.js

@@ -0,0 +1,3 @@
+import text from './transitive.txt';
+
+export { text };

packages/adapter-vercel/test/apps/split/src/lib/transitive.txt

@@ -0,0 +1 @@
+transitive

packages/adapter-vercel/test/apps/split/src/routes/+error.svelte

@@ -0,0 +1,9 @@
+<script>
+	import asset from '$lib/root_error.txt';
+
+	/** @type {import('./$types').PageData}*/
+	export let data;
+</script>
+
+<h1>{data}</h1>
+<p>{asset}</p>

packages/adapter-vercel/test/apps/split/src/routes/+layout.js

@@ -0,0 +1,5 @@
+import layout from '$lib/+layout.js.txt';
+
+export function load({ data }) {
+	return { ...data, layout };
+}

packages/adapter-vercel/test/apps/split/src/routes/+layout.server.js

@@ -0,0 +1,5 @@
+import layout_server from '$lib/+layout.server.js.txt';
+
+export function load() {
+	return { layout_server };
+}

packages/adapter-vercel/test/apps/split/src/routes/+page.server.js

@@ -0,0 +1,5 @@
+import { text } from '$lib/transitive';
+
+export function load() {
+	return { text };
+}

packages/adapter-vercel/test/apps/split/src/routes/api/+server.js

@@ -0,0 +1,5 @@
+import server_asset from '$lib/+server.js.txt';
+
+export function GET() {
+	return new Response(server_asset);
+}

packages/adapter-vercel/test/apps/split/src/routes/load/+error.svelte

@@ -0,0 +1,5 @@
+<script>
+	import asset from '$lib/+error.svelte.txt';
+</script>
+
+<p>{asset}</p>

packages/adapter-vercel/test/apps/split/src/routes/load/+layout.js

@@ -0,0 +1,5 @@
+import layout from '$lib/+layout.js.txt';
+
+export function load() {
+	return { layout };
+}

packages/adapter-vercel/test/apps/split/src/routes/load/+layout.svelte

@@ -0,0 +1,7 @@
+<script>
+	import asset from '$lib/+layout.svelte.txt';
+</script>
+
+<p>{asset}</p>
+
+<slot />

packages/adapter-vercel/test/apps/split/src/routes/load/+page.js

@@ -0,0 +1,5 @@
+import page_data from '$lib/+page.js.txt';
+
+export async function load({ parent, data }) {
+	return { ...data, ...(await parent()), page_data };
+}

packages/adapter-vercel/test/apps/split/src/routes/load/+page.server.js

@@ -0,0 +1,5 @@
+import page_server_text from '$lib/+page.server.js.txt';
+
+export async function load({ parent }) {
+	return { ...(await parent()), page_server_text };
+}

packages/adapter-vercel/test/apps/split/src/routes/load/+page.svelte

@@ -0,0 +1,5 @@
+<script>
+	import asset from '$lib/+page.svelte.txt';
+</script>
+
+<p>{asset}</p>