use path.extname instead of custom getExt helper for determining loader to use

Author: Gavin Sharp

src/utils.ts

@@ -3,19 +3,8 @@ import { Format, Loader, TransformOptions } from 'esbuild'
 
 const loaders = ['js', 'jsx', 'ts', 'tsx', 'json']
 
-const getExt = (str: string) => {
-  const basename = path.basename(str);
-  const firstDot = basename.indexOf('.');
-  const lastDot = basename.lastIndexOf('.');
-  const extname = path.extname(basename).replace(/(\.[a-z0-9]+).*/i, '$1');
-
-  if (firstDot === lastDot) return extname
-
-  return basename.slice(firstDot, lastDot) + extname
-}
-
 export const getEsbuildConfig = (options, filename) => {
-  const ext = getExt(filename),
+  const ext = path.extname(filename),
     extName = path.extname(filename).slice(1)
   const loader = (options?.loaders && options?.loaders[ext]
     ? options.loaders[ext]

tests/utils.spec.ts

@@ -28,7 +28,7 @@ describe('getEsbuildConfig', () => {
       });
     });
 
-    xtest('.js loader returns correct config with compound extension', () => {
+    test('.js loader returns correct config with compound extension', () => {
       const config = getEsbuildConfig(
         { loaders: { '.js': 'jsx' } },
         'filename.test.js'