fix(typescript): resolve js to ts (#15)

package.json

@@ -31,7 +31,7 @@
 		"test": "node --loader @esbuild-kit/esm-loader tests"
 	},
 	"dependencies": {
-		"@esbuild-kit/core-utils": "^1.1.2",
+		"@esbuild-kit/core-utils": "^1.2.0",
 		"es-module-lexer": "^0.10.5",
 		"get-tsconfig": "^3.0.1"
 	},

src/loaders.ts

@@ -2,6 +2,7 @@ import {
 	transform,
 	installSourceMapSupport,
 	transformDynamicImport,
+	resolveTsPath,
 } from '@esbuild-kit/core-utils';
 import getTsconfig from 'get-tsconfig';
 import {
@@ -56,17 +57,18 @@ export const resolve: resolve = async function (
 	}
 
 	/**
-	 * Typescript gives .mts or .cts priority over actual .mjs or .cjs extensions
+	 * Typescript gives .ts, .cts, or .mts priority over actual .js, .cjs, or .mjs extensions
 	 */
-	if (
-		/\.[cm]js$/.test(specifier)
-		&& tsExtensionsPattern.test(context.parentURL!)
-	) {
-		try {
-			return await resolve(`${specifier.slice(0, -2)}ts`, context, defaultResolve);
-		} catch (error) {
-			if ((error as any).code !== 'ERR_MODULE_NOT_FOUND') {
-				throw error;
+	if (tsExtensionsPattern.test(context.parentURL!)) {
+		const tsPath = resolveTsPath(specifier);
+
+		if (tsPath) {
+			try {
+				return await resolve(tsPath, context, defaultResolve);
+			} catch (error) {
+				if ((error as any).code !== 'ERR_MODULE_NOT_FOUND') {
+					throw error;
+				}
 			}
 		}
 	}

tests/specs/typescript/ts.ts

@@ -19,6 +19,20 @@ export default testSuite(async ({ describe }, node: NodeApis) => {
 			});
 		});
 
+		describe('full path via .js', ({ test }) => {
+			const importPath = './lib/ts-ext-ts/index.js';
+
+			test('Load - should not work', async () => {
+				const nodeProcess = await node.load(importPath);
+				expect(nodeProcess.stderr).toMatch('Cannot find module');
+			});
+
+			test('Import', async () => {
+				const nodeProcess = await node.import(importPath, { typescript: true });
+				expect(nodeProcess.stdout).toBe(`${output}\n{"default":1234}`);
+			});
+		});
+
 		describe('extensionless', ({ test }) => {
 			const importPath = './lib/ts-ext-ts/index';