feat: add bun support (#24)

src/index.ts

@@ -1,5 +1,6 @@
 import { promises as fs } from 'node:fs'
 import { basename, dirname, join } from 'node:path'
+import { interopDefault } from 'mlly'
 import jiti from 'jiti'
 import { notNullish, toArray } from '@antfu/utils'
 import defu from 'defu'
@@ -131,14 +132,19 @@ async function loadConfigFile<T>(filepath: string, source: LoadConfigSource<T>):
         config = await parser(filepath)
       }
       else if (parser === 'require') {
-        config = await jiti(filepath, {
-          interopDefault: true,
-          cache: false,
-          v8cache: false,
-          esmResolve: true,
-          // FIXME: https://github.com/unjs/jiti/pull/141
-          requireCache: false,
-        })(bundleFilepath)
+        if (process.versions.bun) {
+          const defaultImport = await import(filepath)
+          config = interopDefault(defaultImport)
+        } else {
+          config = await jiti(filepath, {
+            interopDefault: true,
+            cache: false,
+            v8cache: false,
+            esmResolve: true,
+            // FIXME: https://github.com/unjs/jiti/pull/141
+            requireCache: false,
+          })(bundleFilepath)
+        }
       }
       else if (parser === 'json') {
         config = JSON.parse(await read())