Prerender during build (#4192)

* add config.kit.prerender.default

* prerender during build

* lint

* warn if no fallback and default is false

* use prerendered pages in svelte-kit preview

* make prerendered paths available to service worker

* adapters

* docs

* changesets

* lint

Author: Rich-Harris

.changeset/gorgeous-beans-glow.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+[breaking] expose entire config to adapters, rather than just appDir and trailingSlash

.changeset/khaki-dolls-cough.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+[breaking] replace builder.prerender() with builder.writePrerendered() and builder.prerendered

.changeset/large-berries-exercise.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+[breaking] prerender pages during build, regardless of adapter

.changeset/modern-toys-appear.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Add config.kit.prerender.default option

.changeset/nine-walls-shake.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Use prerendered pages in svelte-kit preview

.changeset/shaggy-days-cheat.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Make prerendered paths available to service workers

.prettierrc

@@ -13,7 +13,7 @@
 		{
 			"files": [
 				"packages/kit/src/packaging/test/fixtures/**/expected/**/*",
-				"packages/kit/src/core/adapt/prerender/fixtures/**/*"
+				"packages/kit/src/core/build/prerender/fixtures/**/*"
 			],
 			"options": {
 				"requirePragma": true

documentation/docs/09-adapters.md

@@ -99,7 +99,7 @@ The types for `Adapter` and its parameters are available in [types/config.d.ts](
 Within the `adapt` method, there are a number of things that an adapter should do:
 
 - Clear out the build directory
-- Call `builder.prerender({ dest })` to prerender pages
+- Write SvelteKit output with `builder.writeClient`, `builder.writePrerendered`, `builder.writeServer`, and `builder.writeStatic`
 - Output code that:
   - Imports `App` from `${builder.getServerDirectory()}/app.js`
   - Instantiates the app with a manifest generated with `builder.generateManifest({ relativePath })`

documentation/docs/10-page-options.md

@@ -38,16 +38,24 @@ Ordinarily, SvelteKit [hydrates](/docs/appendix#hydration) your server-rendered
 
 It's likely that at least some pages of your app can be represented as a simple HTML file generated at build time. These pages can be [_prerendered_](/docs/appendix#prerendering) by your [adapter](/docs/adapters).
 
-If your entire app is suitable for prerendering, you could use [`adapter-static`](https://github.com/sveltejs/kit/tree/master/packages/adapter-static), which will generate HTML files for every page, plus additional files that are requested by `load` functions in those pages.
-
-In many cases, you'll only want to prerender specific pages in your app. You'll need to annotate these pages:
+Prerendering happens automatically for any page with the `prerender` annotation:
 
 ```html
 <script context="module">
 	export const prerender = true;
 </script>
 ```
 
+Alternatively, you can set [`confit.kit.prerender.default`](/docs/configuration#prerender) to `true` and prerender everything except pages that are explicitly marked as _not_ prerenderable:
+
+```html
+<script context="module">
+	export const prerender = false;
+</script>
+```
+
+> If your entire app is suitable for prerendering, you can use [`adapter-static`](https://github.com/sveltejs/kit/tree/master/packages/adapter-static), which will output files suitable for use with any static webserver.
+
 The prerenderer will start at the root of your app and generate HTML for any prerenderable pages it finds. Each page is scanned for `<a>` elements that point to other pages that are candidates for prerendering — because of this, you generally don't need to specify which pages should be accessed. If you _do_ need to specify which pages should be accessed by the prerenderer, you can do so with the `entries` option in the [prerender configuration](/docs/configuration#prerender).
 
 #### When not to prerender

documentation/docs/13-configuration.md

@@ -229,6 +229,7 @@ See [Prerendering](/docs/page-options#prerender). An object containing zero or m
 
 - `concurrency` — how many pages can be prerendered simultaneously. JS is single-threaded, but in cases where prerendering performance is network-bound (for example loading content from a remote CMS) this can speed things up by processing other tasks while waiting on the network response
 - `crawl` — determines whether SvelteKit should find pages to prerender by following links from the seed page(s)
+- `default` — set to `true` to prerender every page without `export const prerender = false`
 - `enabled` — set to `false` to disable prerendering altogether
 - `entries` — an array of pages to prerender, or start crawling from (if `crawl: true`). The `*` string includes all non-dynamic routes (i.e. pages with no `[parameters]` )
 - `onError`

packages/adapter-cloudflare-workers/index.js

@@ -25,9 +25,6 @@ export default function () {
 			builder.rimraf(bucket);
 			builder.rimraf(entrypoint);
 
-			builder.log.info('Prerendering static pages...');
-			const prerendered = await builder.prerender({ dest: bucket });
-
 			builder.log.info('Installing worker dependencies...');
 			builder.copy(`${files}/_package.json`, `${tmp}/package.json`);
 
@@ -49,7 +46,7 @@ export default function () {
 				`${tmp}/manifest.js`,
 				`export const manifest = ${builder.generateManifest({
 					relativePath
-				})};\n\nexport const prerendered = new Set(${JSON.stringify(prerendered.paths)});\n`
+				})};\n\nexport const prerendered = new Set(${JSON.stringify(builder.prerendered.paths)});\n`
 			);
 
 			await esbuild.build({
@@ -65,6 +62,7 @@ export default function () {
 			builder.log.minor('Copying assets...');
 			builder.writeClient(bucket);
 			builder.writeStatic(bucket);
+			builder.writePrerendered(bucket);
 		}
 	};
 }

packages/adapter-cloudflare/index.js

@@ -18,16 +18,15 @@ export default function (options = {}) {
 
 			builder.writeStatic(dest);
 			builder.writeClient(dest);
-
-			const prerendered = await builder.prerender({ dest });
+			builder.writePrerendered(dest);
 
 			const relativePath = posix.relative(tmp, builder.getServerDirectory());
 
 			writeFileSync(
 				`${tmp}/manifest.js`,
 				`export const manifest = ${builder.generateManifest({
 					relativePath
-				})};\n\nexport const prerendered = new Set(${JSON.stringify(prerendered.paths)});\n`
+				})};\n\nexport const prerendered = new Set(${JSON.stringify(builder.prerendered.paths)});\n`
 			);
 
 			builder.copy(`${files}/worker.js`, `${tmp}/_worker.js`, {

packages/adapter-netlify/index.js

@@ -36,11 +36,6 @@ export default function ({ split = false } = {}) {
 
 			builder.log.minor(`Publishing to "${publish}"`);
 
-			builder.log.minor('Prerendering static pages...');
-			await builder.prerender({
-				dest: publish
-			});
-
 			builder.writeServer('.netlify/server');
 
 			// for esbuild, use ESM
@@ -127,6 +122,7 @@ export default function ({ split = false } = {}) {
 			builder.log.minor('Copying assets...');
 			builder.writeStatic(publish);
 			builder.writeClient(publish);
+			builder.writePrerendered(publish);
 
 			builder.log.minor('Writing redirects...');
 			const redirect_file = join(publish, '_redirects');
@@ -138,7 +134,7 @@ export default function ({ split = false } = {}) {
 			builder.copy('_headers', headers_file);
 			appendFileSync(
 				headers_file,
-				`\n\n/${builder.appDir}/*\n  cache-control: public\n  cache-control: immutable\n  cache-control: max-age=31536000\n`
+				`\n\n/${builder.config.kit.appDir}/*\n  cache-control: public\n  cache-control: immutable\n  cache-control: max-age=31536000\n`
 			);
 		}
 	};

packages/adapter-node/index.js

@@ -34,11 +34,7 @@ export default function ({
 			builder.writeClient(`${out}/client`);
 			builder.writeServer(`${out}/server`);
 			builder.writeStatic(`${out}/static`);
-
-			builder.log.minor('Prerendering static pages');
-			await builder.prerender({
-				dest: `${out}/prerendered`
-			});
+			builder.writePrerendered(`${out}/prerendered`);
 
 			writeFileSync(
 				`${out}/manifest.js`,

packages/adapter-static/index.js

@@ -12,17 +12,18 @@ export default function ({ pages = 'build', assets = pages, fallback, precompres
 		name: '@sveltejs/adapter-static',
 
 		async adapt(builder) {
+			if (!fallback && !builder.config.kit.prerender.default) {
+				builder.log.warn(
+					'You should set `config.kit.prerender.default` to `true` if no fallback is specified'
+				);
+			}
+
 			builder.rimraf(assets);
 			builder.rimraf(pages);
 
 			builder.writeStatic(assets);
 			builder.writeClient(assets);
-
-			await builder.prerender({
-				fallback,
-				all: !fallback,
-				dest: pages
-			});
+			builder.writePrerendered(pages, { fallback });
 
 			if (precompress) {
 				if (pages === assets) {

packages/adapter-static/test/apps/prerendered/svelte.config.js

@@ -3,7 +3,11 @@ import adapter from '../../../index.js';
 /** @type {import('@sveltejs/kit').Config} */
 const config = {
 	kit: {
-		adapter: adapter()
+		adapter: adapter(),
+
+		prerender: {
+			default: true
+		}
 	}
 };
 

packages/adapter-vercel/index.js

@@ -100,12 +100,6 @@ export default function ({ external = [] } = {}) {
 				lambda: `${dir}/functions/node/render`
 			};
 
-			builder.log.minor('Prerendering static pages...');
-
-			const prerendered = await builder.prerender({
-				dest: `${dir}/static`
-			});
-
 			builder.log.minor('Generating serverless function...');
 
 			const relativePath = posix.relative(tmp, builder.getServerDirectory());
@@ -139,32 +133,36 @@ export default function ({ external = [] } = {}) {
 
 			builder.writeStatic(dirs.static);
 			builder.writeClient(dirs.static);
+			builder.writePrerendered(dirs.static);
 
 			builder.log.minor('Writing routes...');
 
 			builder.mkdirp(`${dir}/config`);
 
-			const prerendered_pages = Array.from(prerendered.pages, ([src, page]) => ({
+			const prerendered_pages = Array.from(builder.prerendered.pages, ([src, page]) => ({
 				src,
 				dest: page.file
 			}));
 
-			const prerendered_redirects = Array.from(prerendered.redirects, ([src, redirect]) => ({
-				src,
-				headers: {
-					Location: redirect.location
-				},
-				status: redirect.status
-			}));
+			const prerendered_redirects = Array.from(
+				builder.prerendered.redirects,
+				([src, redirect]) => ({
+					src,
+					headers: {
+						Location: redirect.location
+					},
+					status: redirect.status
+				})
+			);
 
 			writeFileSync(
 				`${dir}/config/routes.json`,
 				JSON.stringify([
-					...redirects[builder.trailingSlash],
+					...redirects[builder.config.kit.trailingSlash],
 					...prerendered_pages,
 					...prerendered_redirects,
 					{
-						src: `/${builder.appDir}/.+`,
+						src: `/${builder.config.kit.appDir}/.+`,
 						headers: {
 							'cache-control': 'public, immutable, max-age=31536000'
 						}

packages/kit/src/cli.js

@@ -5,6 +5,7 @@ import * as ports from 'port-authority';
 import { load_config } from './core/config/index.js';
 import { networkInterfaces, release } from 'os';
 import { coalesce_to_error } from './utils/error.js';
+import { logger } from './core/utils.js';
 
 /** @param {unknown} e */
 function handle_error(e) {
@@ -91,16 +92,18 @@ prog
 			process.env.NODE_ENV = process.env.NODE_ENV || 'production';
 			const config = await load_config();
 
+			const log = logger({ verbose });
+
 			const { build } = await import('./core/build/index.js');
-			const build_data = await build(config);
+			const { build_data, prerendered } = await build(config, { log });
 
 			console.log(
 				`\nRun ${colors.bold().cyan('npm run preview')} to preview your production build locally.`
 			);
 
 			if (config.kit.adapter) {
 				const { adapt } = await import('./core/adapt/index.js');
-				await adapt(config, build_data, { verbose });
+				await adapt(config, build_data, prerendered, { log });
 
 				// this is necessary to close any open db connections, etc
 				process.exit(0);