Support tsconfig aliases in styles

.changeset/empty-ravens-complain.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Support tsconfig aliases in styles

packages/astro/src/vite-plugin-config-alias/index.ts

@@ -1,47 +1,20 @@
-import * as path from 'path';
+import fs from 'fs';
+import path from 'path';
 import type { AstroSettings } from '../@types/astro';
 
-import type * as vite from 'vite';
-
-/** Result of successfully parsed tsconfig.json or jsconfig.json. */
-export declare interface Alias {
-	find: RegExp;
-	replacement: string;
-}
-
-/** Returns a path with its slashes replaced with posix slashes. */
-const normalize = (pathname: string) => String(pathname).split(path.sep).join(path.posix.sep);
+import type { Alias, Plugin as VitePlugin } from 'vite';
+import type { TsConfigJson } from 'tsconfig-resolver';
+import slash from 'slash';
 
 /** Returns a list of compiled aliases. */
-const getConfigAlias = (settings: AstroSettings): Alias[] | null => {
-	/** Closest tsconfig.json or jsconfig.json */
-	const config = settings.tsConfig;
-	const configPath = settings.tsConfigPath;
-
-	// if no config was found, return null
-	if (!config || !configPath) return null;
-
-	/** Compiler options from tsconfig.json or jsconfig.json. */
-	const compilerOptions = Object(config.compilerOptions);
-
-	// if no compilerOptions.baseUrl was defined, return null
-	if (!compilerOptions.baseUrl) return null;
-
-	// resolve the base url from the configuration file directory
-	const baseUrl = path.posix.resolve(
-		path.posix.dirname(normalize(configPath).replace(/^\/?/, '/')),
-		normalize(compilerOptions.baseUrl)
-	);
-
-	/** List of compiled alias expressions. */
+const getConfigAlias = (
+	paths: NonNullable<TsConfigJson.CompilerOptions['paths']>,
+	baseUrl: NonNullable<TsConfigJson.CompilerOptions['baseUrl']>
+): Alias[] => {
 	const aliases: Alias[] = [];
 
 	// compile any alias expressions and push them to the list
-	for (let [alias, values] of Object.entries(
-		Object(compilerOptions.paths) as { [key: string]: string[] }
-	)) {
-		values = [].concat(values as never);
-
+	for (const [alias, values] of Object.entries(paths)) {
 		/** Regular Expression used to match a given path. */
 		const find = new RegExp(
 			`^${[...alias]
@@ -54,7 +27,7 @@ const getConfigAlias = (settings: AstroSettings): Alias[] | null => {
 		/** Internal index used to calculate the matching id in a replacement. */
 		let matchId = 0;
 
-		for (let value of values) {
+		for (const value of values) {
 			/** String used to replace a matched path. */
 			const replacement = [...path.posix.resolve(baseUrl, value)]
 				.map((segment) => (segment === '*' ? `$${++matchId}` : segment === '$' ? '$$' : segment))
@@ -64,14 +37,6 @@ const getConfigAlias = (settings: AstroSettings): Alias[] | null => {
 		}
 	}
 
-	// compile the baseUrl expression and push it to the list
-	// - `baseUrl` changes the way non-relative specifiers are resolved
-	// - if `baseUrl` exists then all non-relative specifiers are resolved relative to it
-	aliases.push({
-		find: /^(?!\.*\/)(.+)$/,
-		replacement: `${[...baseUrl].map((segment) => (segment === '$' ? '$$' : segment)).join('')}/$1`,
-	});
-
 	return aliases;
 };
 
@@ -80,39 +45,42 @@ export default function configAliasVitePlugin({
 	settings,
 }: {
 	settings: AstroSettings;
-}): vite.PluginOption {
-	const { config } = settings;
-	/** Aliases from the tsconfig.json or jsconfig.json configuration. */
-	const configAlias = getConfigAlias(settings);
+}): VitePlugin | null {
+	const { tsConfig, tsConfigPath } = settings;
+	if (!tsConfig || !tsConfigPath || !tsConfig.compilerOptions) return null;
+
+	const { baseUrl, paths } = tsConfig.compilerOptions;
+	if (!baseUrl || !paths) return null;
+
+	// resolve the base url from the configuration file directory
+	const resolvedBaseUrl = path.posix.resolve(
+		path.posix.dirname(slash(tsConfigPath).replace(/^\/?/, '/')),
+		slash(baseUrl)
+	);
 
-	// if no config alias was found, bypass this plugin
-	if (!configAlias) return {} as vite.PluginOption;
+	const configAlias = getConfigAlias(paths, resolvedBaseUrl);
 
 	return {
 		name: 'astro:tsconfig-alias',
 		enforce: 'pre',
-		async resolveId(sourceId: string, importer, options) {
-			/** Resolved ID conditionally handled by any other resolver. (this gives priority to all other resolvers) */
-			const resolvedId = await this.resolve(sourceId, importer, { skipSelf: true, ...options });
-
-			// if any other resolver handles the file, return that resolution
-			if (resolvedId) return resolvedId;
-
-			// conditionally resolve the source ID from any matching alias or baseUrl
-			for (const alias of configAlias) {
-				if (alias.find.test(sourceId)) {
-					/** Processed Source ID with our alias applied. */
-					const aliasedSourceId = sourceId.replace(alias.find, alias.replacement);
-
-					/** Resolved ID conditionally handled by any other resolver. (this also gives priority to all other resolvers) */
-					const resolvedAliasedId = await this.resolve(aliasedSourceId, importer, {
-						skipSelf: true,
-						...options,
-					});
-
-					// if the existing resolvers find the file, return that resolution
-					if (resolvedAliasedId) return resolvedAliasedId;
-				}
+		config() {
+			if (configAlias.length) {
+				return {
+					resolve: {
+						alias: configAlias,
+					},
+				};
+			}
+		},
+		resolveId(id) {
+			if (id.startsWith('.') || id.startsWith('/')) return;
+
+			// Handle baseUrl mapping for non-relative and non-root imports.
+			// Since TypeScript only applies `baseUrl` autocompletions for files that exist
+			// in the filesystem only, we can use this heuristic to skip resolve if needed.
+			const resolved = path.posix.join(resolvedBaseUrl, id);
+			if (fs.existsSync(resolved)) {
+				return resolved;
 			}
 		},
 	};

packages/astro/test/alias-tsconfig.test.js

@@ -34,5 +34,20 @@ describe('Aliases with tsconfig.json', () => {
 			const scripts = $('script').toArray();
 			expect(scripts.length).to.be.greaterThan(0);
 		});
+
+		it('can load via baseUrl', async () => {
+			const html = await fixture.fetch('/').then((res) => res.text());
+			const $ = cheerio.load(html);
+
+			expect($('#foo').text()).to.equal('foo');
+		});
+
+		it('works in css @import', async () => {
+			const html = await fixture.fetch('/').then((res) => res.text());
+			console.log(html)
+			// imported css should be bundled
+			expect(html).to.include('#style-red');
+			expect(html).to.include('#style-blue');
+		});
 	});
 });

packages/astro/test/fixtures/alias-tsconfig/src/components/Foo.astro

@@ -0,0 +1 @@
+<p id="foo">foo</p>

packages/astro/test/fixtures/alias-tsconfig/src/components/Style.astro

@@ -0,0 +1,2 @@
+<p id="style-blue">i am blue</p>
+<p id="style-red">i am red</p>

packages/astro/test/fixtures/alias-tsconfig/src/pages/index.astro

@@ -1,5 +1,8 @@
 ---
 import Client from '@components/Client.svelte'
+import Foo from 'src/components/Foo.astro';
+import StyleComp from 'src/components/Style.astro';
+import '@styles/main.css'
 ---
 <html lang="en">
   <head>
@@ -10,6 +13,8 @@ import Client from '@components/Client.svelte'
   <body>
     <main>
       <Client client:load />
+      <Foo />
+      <StyleComp />
     </main>
   </body>
 </html>

packages/astro/test/fixtures/alias-tsconfig/src/styles/extra.css

@@ -0,0 +1,3 @@
+#style-red {
+  color: red;
+}

packages/astro/test/fixtures/alias-tsconfig/src/styles/main.css

@@ -0,0 +1,5 @@
+@import "@styles/extra.css";
+
+#style-blue {
+  color: blue;
+}

packages/astro/test/fixtures/alias-tsconfig/tsconfig.json

@@ -5,12 +5,9 @@
       "@components/*": [
         "src/components/*"
       ],
-      "@layouts/*": [
-        "src/layouts/*"
-      ],
-      "@assets/*": [
-        "src/assets/*"
-      ],
+      "@styles/*": [
+        "src/styles/*"
+      ]
     }
   }
 }