Inline small hoisted scripts (#3658)

* Inline small hoisted scripts

This makes it so that small hoisted scripts get inlined into the page rather than be fetched externally.

* Ensure we don't inline when there are imports

* Fix ts

* Update tests with new url structure

* Adds a changeset

.changeset/violet-terms-live.md

@@ -0,0 +1,7 @@
+---
+'astro': patch
+---
+
+Inlines small hoisted scripts
+
+This enables a perf improvement, whereby small hoisted scripts without dependencies are inlined into the HTML, rather than loaded externally. This uses `vite.build.assetInlineLimit` to determine if the script should be inlined.

packages/astro/src/core/app/index.ts

@@ -3,6 +3,7 @@ import type {
 	EndpointHandler,
 	ManifestData,
 	RouteData,
+	SSRElement,
 } from '../../@types/astro';
 import type { LogOptions } from '../logger/core.js';
 import type { RouteInfo, SSRManifest as Manifest } from './types';
@@ -16,6 +17,7 @@ import { RouteCache } from '../render/route-cache.js';
 import {
 	createLinkStylesheetElementSet,
 	createModuleScriptElementWithSrcSet,
+	createModuleScriptElement,
 } from '../render/ssr-element.js';
 import { matchRoute } from '../routing/match.js';
 export { deserializeManifest } from './common.js';
@@ -79,19 +81,18 @@ export class App {
 		const info = this.#routeDataToRouteInfo.get(routeData!)!;
 		const links = createLinkStylesheetElementSet(info.links, manifest.site);
 
-		const filteredScripts = info.scripts.filter(
-			(script) => typeof script === 'string' || script?.stage !== 'head-inline'
-		) as string[];
-		const scripts = createModuleScriptElementWithSrcSet(filteredScripts, manifest.site);
-
-		// Add all injected scripts to the page.
+		let scripts = new Set<SSRElement>();
 		for (const script of info.scripts) {
-			if (typeof script !== 'string' && script.stage === 'head-inline') {
+			if (('stage' in script)) {
+				if(script.stage === 'head-inline') {
 					scripts.add({
 						props: {},
 						children: script.children,
 					});
 				}
+			} else {
+				scripts.add(createModuleScriptElement(script, manifest.site));
+			}
 		}
 
 		const result = await render({

packages/astro/src/core/app/types.ts

@@ -12,7 +12,13 @@ export interface RouteInfo {
 	routeData: RouteData;
 	file: string;
 	links: string[];
-	scripts: Array<string | { children: string; stage: string }>;
+	scripts:
+		(
+			// Integration injected
+			{ children: string; stage: string } |
+			// Hoisted
+			{ type: 'inline' | 'external'; value: string; }
+		)[];
 }
 
 export type SerializedRouteInfo = Omit<RouteInfo, 'routeData'> & {

packages/astro/src/core/build/generate.ts

@@ -18,7 +18,7 @@ import { debug, info } from '../logger/core.js';
 import { render } from '../render/core.js';
 import {
 	createLinkStylesheetElementSet,
-	createModuleScriptElementWithSrcSet,
+	createModuleScriptsSet,
 } from '../render/ssr-element.js';
 import { createRequest } from '../request.js';
 import { getOutputFilename, isBuildingToSSR } from '../util.js';
@@ -124,7 +124,7 @@ async function generatePage(
 
 	const pageInfo = getPageDataByComponent(internals, pageData.route.component);
 	const linkIds: string[] = Array.from(pageInfo?.css ?? []);
-	const hoistedId = pageInfo?.hoistedScript ?? null;
+	const scripts = pageInfo?.hoistedScript ?? null;
 
 	const pageModule = ssrEntry.pageMap.get(pageData.component);
 
@@ -143,7 +143,7 @@ async function generatePage(
 		pageData,
 		internals,
 		linkIds,
-		hoistedId,
+		scripts,
 		mod: pageModule,
 		renderers,
 	};
@@ -167,7 +167,7 @@ interface GeneratePathOptions {
 	pageData: PageBuildData;
 	internals: BuildInternals;
 	linkIds: string[];
-	hoistedId: string | null;
+	scripts: { type: 'inline' | 'external', value: string } | null;
 	mod: ComponentInstance;
 	renderers: SSRLoadedRenderer[];
 }
@@ -182,7 +182,7 @@ async function generatePath(
 	gopts: GeneratePathOptions
 ) {
 	const { astroConfig, logging, origin, routeCache } = opts;
-	const { mod, internals, linkIds, hoistedId, pageData, renderers } = gopts;
+	const { mod, internals, linkIds, scripts: hoistedScripts, pageData, renderers } = gopts;
 
 	// This adds the page name to the array so it can be shown as part of stats.
 	if (pageData.route.type === 'page') {
@@ -198,7 +198,7 @@ async function generatePath(
 			? joinPaths(astroConfig.site?.toString() || 'http://localhost/', astroConfig.base)
 			: astroConfig.site;
 	const links = createLinkStylesheetElementSet(linkIds.reverse(), site);
-	const scripts = createModuleScriptElementWithSrcSet(hoistedId ? [hoistedId] : [], site);
+	const scripts = createModuleScriptsSet(hoistedScripts ? [hoistedScripts] : [], site);
 
 	// Add all injected scripts to the page.
 	for (const script of astroConfig._ctx.scripts) {

packages/astro/src/core/build/page-data.ts

@@ -69,7 +69,6 @@ export async function collectPagesData(
 				moduleSpecifier: '',
 				css: new Set(),
 				hoistedScript: undefined,
-				scripts: new Set(),
 			};
 
 			clearInterval(routeCollectionLogTimeout);
@@ -131,7 +130,6 @@ export async function collectPagesData(
 			moduleSpecifier: '',
 			css: new Set(),
 			hoistedScript: undefined,
-			scripts: new Set(),
 		};
 	}
 

packages/astro/src/core/build/static-build.ts

@@ -117,8 +117,8 @@ async function ssrBuild(opts: StaticBuildOptions, internals: BuildInternals, inp
 				output: {
 					format: 'esm',
 					entryFileNames: opts.buildConfig.serverEntry,
-					chunkFileNames: 'chunks/chunk.[hash].mjs',
-					assetFileNames: 'assets/asset.[hash][extname]',
+					chunkFileNames: 'chunks/[name].[hash].mjs',
+					assetFileNames: 'assets/[name].[hash][extname]',
 					...viteConfig.build?.rollupOptions?.output,
 				},
 			},
@@ -202,9 +202,9 @@ async function clientBuild(
 				input: Array.from(input),
 				output: {
 					format: 'esm',
-					entryFileNames: 'entry.[hash].js',
-					chunkFileNames: 'chunks/chunk.[hash].js',
-					assetFileNames: 'assets/asset.[hash][extname]',
+					entryFileNames: '[name].[hash].js',
+					chunkFileNames: 'chunks/[name].[hash].js',
+					assetFileNames: 'assets/[name].[hash][extname]',
 					...viteConfig.build?.rollupOptions?.output,
 				},
 				preserveEntrySignatures: 'exports-only',

packages/astro/src/core/build/types.ts

@@ -19,8 +19,7 @@ export interface PageBuildData {
 	route: RouteData;
 	moduleSpecifier: string;
 	css: Set<string>;
-	hoistedScript: string | undefined;
-	scripts: Set<string>;
+	hoistedScript: { type: 'inline' | 'external', value: string } | undefined;
 }
 export type AllPagesData = Record<ComponentPath, PageBuildData>;
 

packages/astro/src/core/build/vite-plugin-hoisted-scripts.ts

@@ -40,6 +40,8 @@ export function vitePluginHoistedScripts(
 		},
 
 		async generateBundle(_options, bundle) {
+			let assetInlineLimit = astroConfig.vite?.build?.assetsInlineLimit || 4096;
+
 			// Find all page entry points and create a map of the entry point to the hashed hoisted script.
 			// This is used when we render so that we can add the script to the head.
 			for (const [id, output] of Object.entries(bundle)) {
@@ -48,16 +50,35 @@ export function vitePluginHoistedScripts(
 					output.facadeModuleId &&
 					virtualHoistedEntry(output.facadeModuleId)
 				) {
+					const canBeInlined = output.imports.length === 0 && output.dynamicImports.length === 0 &&
+						Buffer.byteLength(output.code) <= assetInlineLimit;
+					let removeFromBundle = false;
 					const facadeId = output.facadeModuleId!;
 					const pages = internals.hoistedScriptIdToPagesMap.get(facadeId)!;
 					for (const pathname of pages) {
 						const vid = viteID(new URL('.' + pathname, astroConfig.root));
 						const pageInfo = getPageDataByViteID(internals, vid);
 						if (pageInfo) {
-							pageInfo.hoistedScript = id;
+							if(canBeInlined) {
+								pageInfo.hoistedScript = {
+									type: 'inline',
+									value: output.code
+								};
+								removeFromBundle = true;
+							} else {
+								pageInfo.hoistedScript = {
+									type: 'external',
+									value: id
+								};
 							}
 						}
 					}
+
+					// Remove the bundle if it was inlined
+					if(removeFromBundle) {
+						delete bundle[id];
+					}
+				}
 			}
 		},
 	};

packages/astro/src/core/build/vite-plugin-ssr.ts

@@ -129,7 +129,7 @@ function buildManifest(
 	const routes: SerializedRouteInfo[] = [];
 
 	for (const pageData of eachPageData(internals)) {
-		const scripts = Array.from(pageData.scripts);
+		const scripts: SerializedRouteInfo['scripts'] = [];
 		if (pageData.hoistedScript) {
 			scripts.unshift(pageData.hoistedScript);
 		}

packages/astro/src/core/render/ssr-element.ts

@@ -25,6 +25,19 @@ export function createLinkStylesheetElementSet(hrefs: string[], site?: string) {
 	return new Set<SSRElement>(hrefs.map((href) => createLinkStylesheetElement(href, site)));
 }
 
+export function createModuleScriptElement(script: { type: 'inline' | 'external'; value: string; }, site?: string): SSRElement {
+	if(script.type === 'external') {
+		return createModuleScriptElementWithSrc(script.value, site);
+	} else {
+		return {
+			props: {
+				type: 'module',
+			},
+			children: script.value,
+		};
+	}
+}
+
 export function createModuleScriptElementWithSrc(src: string, site?: string): SSRElement {
 	return {
 		props: {
@@ -41,3 +54,10 @@ export function createModuleScriptElementWithSrcSet(
 ): Set<SSRElement> {
 	return new Set<SSRElement>(srces.map((src) => createModuleScriptElementWithSrc(src, site)));
 }
+
+export function createModuleScriptsSet(
+	scripts: { type: 'inline' | 'external'; value: string; }[],
+	site?: string
+): Set<SSRElement> {
+	return new Set<SSRElement>(scripts.map(script => createModuleScriptElement(script, site)));
+}

packages/astro/test/astro-dynamic.test.js

@@ -36,7 +36,7 @@ describe('Dynamic components', () => {
 		expect($('astro-island').html()).to.equal('');
 		// test 2: component url
 		const href = $('astro-island').attr('component-url');
-		expect(href).to.include(`/entry`);
+		expect(href).to.include(`/PersistentCounter`);
 	});
 });
 
@@ -75,6 +75,6 @@ describe('Dynamic components subpath', () => {
 		expect($('astro-island').html()).to.equal('');
 		// test 2: has component url
 		const attr = $('astro-island').attr('component-url');
-		expect(attr).to.include(`blog/entry`);
+		expect(attr).to.include(`blog/PersistentCounter`);
 	});
 });

packages/astro/test/astro-scripts.test.js

@@ -37,15 +37,16 @@ describe('Scripts (hoisted and not)', () => {
 		// Inline page
 		let inline = await fixture.readFile('/inline/index.html');
 		let $ = cheerio.load(inline);
+		let $el = $('script');
 
 		// test 1: Just one entry module
-		expect($('script')).to.have.lengthOf(1);
+		expect($el).to.have.lengthOf(1);
 
 		// test 2: attr removed
-		expect($('script').attr('data-astro')).to.equal(undefined);
+		expect($el.attr('data-astro')).to.equal(undefined);
 
-		const entryURL = $('script').attr('src');
-		const inlineEntryJS = await fixture.readFile(entryURL);
+		expect($el.attr('src')).to.equal(undefined);
+		const inlineEntryJS = $el.text();
 
 		// test 3: the JS exists
 		expect(inlineEntryJS).to.be.ok;
@@ -57,6 +58,14 @@ describe('Scripts (hoisted and not)', () => {
 		);
 	});
 
+	it('Inline scripts that are shared by multiple pages create chunks, and aren\'t inlined into the HTML', async () => {
+		let html = await fixture.readFile('/inline-shared-one/index.html');
+		let $ = cheerio.load(html);
+
+		expect($('script')).to.have.lengthOf(1);
+		expect($('script').attr('src')).to.not.equal(undefined);
+	});
+
 	it('External page builds the hoisted scripts to a single bundle', async () => {
 		let external = await fixture.readFile('/external/index.html');
 		let $ = cheerio.load(external);
@@ -65,8 +74,8 @@ describe('Scripts (hoisted and not)', () => {
 		expect($('script')).to.have.lengthOf(2);
 
 		let el = $('script').get(1);
-		let entryURL = $(el).attr('src');
-		let externalEntryJS = await fixture.readFile(entryURL);
+		expect($(el).attr('src')).to.equal(undefined, 'This should have been inlined');
+		let externalEntryJS = $(el).text();
 
 		// test 2: the JS exists
 		expect(externalEntryJS).to.be.ok;

packages/astro/test/fixtures/astro-scripts/src/components/InlineShared.astro

@@ -0,0 +1,3 @@
+<script>
+	console.log('im a inlined script');
+</script>

packages/astro/test/fixtures/astro-scripts/src/pages/inline-shared-one.astro

@@ -0,0 +1,14 @@
+---
+import InlineShared from '../components/InlineShared.astro';
+---
+<html>
+	<head>
+		<title>Testing</title>
+	</head>
+	<body>
+		<InlineShared />
+		<script>
+			console.log("page one");
+		</script>
+	</body>
+</html>

packages/astro/test/fixtures/astro-scripts/src/pages/inline-shared-two.astro

@@ -0,0 +1,14 @@
+---
+import InlineShared from '../components/InlineShared.astro';
+---
+<html>
+	<head>
+		<title>Testing</title>
+	</head>
+	<body>
+		<InlineShared />
+		<script>
+			console.log("page two");
+		</script>
+	</body>
+</html>