Update loaders.ts

Author: mshima

src/loaders.ts

@@ -37,22 +37,18 @@ type resolve = (
 
 const extensions = ['.js', '.json', '.ts', '.tsx', '.jsx'] as const;
 
-const mappedExtensions = {
-	'.js': ['.ts'],
-	'.cjs': ['.cts'],
-	'.mjs': ['.mts'],
-} as const;
-
 async function tryExtensions(
 	specifier: string,
 	context: Context,
 	defaultResolve: resolve,
 ) {
 	let error;
-	const extension = path.extname(specifier);
-	let extensionsToTry = mappedExtensions[extension];
-	if (extensionsToTry) {
+	const tsSpecifier = resolveTsPath(specifier);
+	let extensionsToTry;
+	if (tsSpecifier) {
+		const extension = path.extname(specifier);
 		specifier = specifier.slice(0, -extension.length);
+		extensionsToTry = [extension];
 	} else {
 		extensionsToTry = extensions;
 	}