Use stat instead of extname when creating require (#4860)

Author: adambrgmn

.changeset/rotten-flies-sort.md

@@ -0,0 +1,5 @@
+---
+'@graphql-codegen/cli': patch
+---
+
+Use `fs.statSync` when creating custom require instead of `path.extname`

packages/graphql-codegen-cli/src/codegen.ts

@@ -15,12 +15,13 @@ import { getPresetByName } from './presets';
 import { debugLog } from './utils/debugging';
 import { printSchemaWithDirectives } from '@graphql-tools/utils';
 import { CodegenContext, ensureContext } from './config';
+import fs from 'fs';
 import path from 'path';
 // eslint-disable-next-line
 import { createRequire, createRequireFromPath } from 'module';
 
 const makeDefaultLoader = (from: string) => {
-  if (!path.extname(from)) {
+  if (fs.statSync(from).isDirectory()) {
     from = path.join(from, '__fake.js');
   }