fix

src/configurer/configurer.ts

@@ -43,7 +43,7 @@ export class Configurer<T extends Record<string, string>> {
   constructor(public defaultConfig: T) {}
 
   loadConfig(
-    options: { env?: Record<string, string>; obj?: any } = {},
+    options: { env?: Record<string, string | undefined>; obj?: any } = {},
   ): ConfigurerInstance<T> {
     const readConfig =
       options?.obj && typeof options.obj === 'object' ? options.obj : {};