fix(esm): implicit resolution with tsconfig paths

fixes #607

Author: privatenumber

src/esm/hook/resolve.ts

@@ -92,28 +92,6 @@ const resolveBase: ResolveHook = async (
 	context,
 	nextResolve,
 ) => {
-	// If directory, can be index.js, index.ts, etc.
-
-	// Resolve TS alias
-	// Bare specifier
-	if (
-		!requestAcceptsQuery(specifier)
-		// TS path alias
-		&& tsconfigPathsMatcher
-		&& !context.parentURL?.includes('/node_modules/')
-	) {
-		const possiblePaths = tsconfigPathsMatcher(specifier);
-		for (const possiblePath of possiblePaths) {
-			try {
-				return await resolveBase(
-					pathToFileURL(possiblePath).toString(),
-					context,
-					nextResolve,
-				);
-			} catch {}
-		}
-	}
-
 	const isBarePackageName = isBarePackageNamePattern.test(specifier);
 
 	// Typescript gives .ts, .cts, or .mts priority over actual .js, .cjs, or .mjs extensions
@@ -160,11 +138,10 @@ const resolveDirectory: ResolveHook = async (
 	context,
 	nextResolve,
 ) => {
-	const [specifierWithoutQuery, query] = specifier.split('?');
-
 	if (isDirectoryPattern.test(specifier)) {
+		// If directory, can be index.js, index.ts, etc.
 		return (await resolveExtensions(
-			`${specifierWithoutQuery}index${query ? `?${query}` : ''}`,
+			`${specifier}index`,
 			context,
 			nextResolve,
 			true,
@@ -181,7 +158,7 @@ const resolveDirectory: ResolveHook = async (
 				if (errorPath) {
 					try {
 						return (await resolveExtensions(
-							`${errorPath}/index${query ? `?${query}` : ''}`,
+							`${errorPath}/index`,
 							context,
 							nextResolve,
 							true,
@@ -201,6 +178,33 @@ const resolveDirectory: ResolveHook = async (
 	}
 };
 
+const resolveTsPaths: ResolveHook = async (
+	specifier,
+	context,
+	nextResolve,
+) => {
+	if (
+		// Bare specifier
+		!requestAcceptsQuery(specifier)
+		// TS path alias
+		&& tsconfigPathsMatcher
+		&& !context.parentURL?.includes('/node_modules/')
+	) {
+		const possiblePaths = tsconfigPathsMatcher(specifier);
+		for (const possiblePath of possiblePaths) {
+			try {
+				return await resolveDirectory(
+					pathToFileURL(possiblePath).toString(),
+					context,
+					nextResolve,
+				);
+			} catch {}
+		}
+	}
+
+	return resolveDirectory(specifier, context, nextResolve);
+};
+
 export const resolve: ResolveHook = async (
 	specifier,
 	context,
@@ -219,8 +223,10 @@ export const resolve: ResolveHook = async (
 		return nextResolve(specifier, context);
 	}
 
-	const resolved = await resolveDirectory(
-		specifier,
+	const [cleanSpecifier, query] = specifier.split('?');
+
+	const resolved = await resolveTsPaths(
+		cleanSpecifier,
 		context,
 		nextResolve,
 	);
@@ -237,11 +243,14 @@ export const resolve: ResolveHook = async (
 		resolved.format = await getFormatFromFileUrl(resolved.url);
 	}
 
+	if (query) {
+		resolved.url += `?${query}`;
+	}
+
 	// Inherit namespace
 	if (
 		requestNamespace
 		&& !resolved.url.includes(namespaceQuery)
-		&& requestAcceptsQuery(resolved.url)
 	) {
 		resolved.url += (resolved.url.includes('?') ? '&' : '?') + namespaceQuery + requestNamespace;
 	}

tests/fixtures.ts

@@ -251,6 +251,14 @@ export const files = {
 	${sourcemap.test('cts')}
 	`,
 
+	'tsconfig.json': createTsconfig({
+		compilerOptions: {
+			paths: {
+				'@/*': ['./*'],
+			},
+		},
+	}),
+
 	'file.txt': 'hello',
 
 	'broken-syntax.ts': 'if',

tests/specs/smoke.ts

@@ -44,8 +44,11 @@ export default testSuite(async ({ describe }, { tsx, supports, version }: NodeAp
 						// .js in esm syntax
 						import * as js from './js/index.js';
 						import './js/index.js?query=123';
+						import '@/js/index.js?query=123';
 						import './js/index';
+						import '@/js/index';
 						import './js/';
+						import '@/js/';
 
 						// No double .default.default in Dynamic Import
 						import/* comment */('./js/index.js').then(m => {
@@ -63,7 +66,9 @@ export default testSuite(async ({ describe }, { tsx, supports, version }: NodeAp
 						// .json
 						import * as json from './json/index.json';
 						import './json/index';
+						import '@/json/index';
 						import './json/';
+						import '@/json/';
 
 						// .cjs
 						import * as cjs from './cjs/index.cjs';
@@ -202,6 +207,7 @@ export default testSuite(async ({ describe }, { tsx, supports, version }: NodeAp
 						// .js in esm syntax
 						import * as js from './js/index.js';
 						import './js/index.js?query=123';
+						import '@/js/index.js?query=123';
 						import './js/index';
 						import './js/';
 
@@ -265,26 +271,37 @@ export default testSuite(async ({ describe }, { tsx, supports, version }: NodeAp
 						// .ts
 						import './ts/index.ts';
 						import './ts/index.js';
+						import '@/ts/index.js';
 						import './ts/index.jsx';
 						import './ts/index';
+						import '@/ts/index';
 						import './ts/';
+						import '@/ts/';
 						import './ts/period.in.name';
+						import '@/ts/period.in.name';
 
 						// .jsx
 						import * as jsx from './jsx/index.jsx';
 						import './jsx/index.js';
+						import '@/jsx/index.js';
 						import './jsx/index';
+						import '@/jsx/index';
 						import './jsx/';
+						import '@/jsx/';
 
 						// .tsx
 						import './tsx/index.tsx';
 						import './tsx/index.js';
 						import './tsx/index.jsx';
+						import '@/tsx/index.jsx';
 						import './tsx/index';
+						import '@/tsx/index';
 						import './tsx/';
+						import '@/tsx/';
 
 						// .cts
 						import './cts/index.cjs';
+						import '@/cts/index.cjs';
 						expectErrors(
 							// TODO:
 							// [() => import ('./cts/index.cts'), 'Cannot find module'],
@@ -303,6 +320,7 @@ export default testSuite(async ({ describe }, { tsx, supports, version }: NodeAp
 
 						// .mts
 						import './mts/index.mjs';
+						import '@/mts/index.mjs';
 						expectErrors(
 							// TODO:
 							// [() => import ('./mts/index.mts'), 'Cannot find module'],