fix: always ensure isDir for filename

src/jiti.ts

@@ -7,6 +7,7 @@ import { createHash } from 'crypto'
 import mkdirp from 'mkdirp'
 import createRequire from 'create-require'
 import resolve from 'resolve'
+import { isDir } from './utils'
 import { TransformOptions } from './types'
 
 export type JITIOptions = {
@@ -25,9 +26,14 @@ function md5 (content: string, len = 8) {
   return createHash('md5').update(content).digest('hex').substr(0, len)
 }
 
-export default function createJITI (_filename: string = process.cwd() + '/index.js', opts: JITIOptions = {}): NodeRequire {
+export default function createJITI (_filename: string = process.cwd(), opts: JITIOptions = {}): NodeRequire {
   opts = { ...defaults, ...opts }
 
+  // If filename is dir, createRequire goes with parent directory, so we need fakepath
+  if (isDir(_filename)) {
+    _filename = join(_filename, 'index.js')
+  }
+
   if (opts.cache && !opts.cacheDir) {
     const nodeModulesDir = join(process.cwd(), 'node_modules')
     if (existsSync(nodeModulesDir)) {

src/utils.ts

@@ -0,0 +1,11 @@
+import { lstatSync } from 'fs'
+
+export function isDir (filename: string): boolean {
+  try {
+    const stat = lstatSync(filename)
+    return stat.isDirectory()
+  } catch (e) {
+    // lstatSync throws an error if path doesn't exist
+    return false
+  }
+}