diff --git a/src/utils/package.test.ts b/src/utils/package.test.ts
index 52de2f7..3674156 100644
--- a/src/utils/package.test.ts
+++ b/src/utils/package.test.ts
@@ -13,9 +13,9 @@ describe('formatLicense', (): void => {
   });
 
   test('should check license field for other value', (): void => {
-    expect(formatLicense(null)).toBeNull();
-    expect(formatLicense({})).toBeNull();
-    expect(formatLicense([])).toBeNull();
+    expect(formatLicense(null)).toBeUndefined();
+    expect(formatLicense({})).toBeUndefined();
+    expect(formatLicense([])).toBeUndefined();
   });
 });
 
diff --git a/src/utils/package.ts b/src/utils/package.ts
index 485885a..eacd5ab 100644
--- a/src/utils/package.ts
+++ b/src/utils/package.ts
@@ -12,7 +12,7 @@ export const TIMEFORMAT = 'DD.MM.YYYY, HH:mm:ss';
  */
 // License should use type License defined above, but conflicts with the unit test that provide array or empty object
 /* eslint-disable @typescript-eslint/no-explicit-any */
-export function formatLicense(license: any): string | null {
+export function formatLicense(license: any): string | undefined {
   if (isString(license)) {
     return license;
   }
@@ -21,7 +21,7 @@ export function formatLicense(license: any): string | null {
     return license.type;
   }
 
-  return null;
+  return;
 }
 
 export interface Repository {
diff --git a/types/packageMeta.ts b/types/packageMeta.ts
index bc86360..171095d 100644
--- a/types/packageMeta.ts
+++ b/types/packageMeta.ts
@@ -5,7 +5,7 @@ export interface PackageMetaInterface {
       fileCount: number;
       unpackedSize: number;
     };
-    license?: Partial<LicenseInterface> | string | null;
+    license?: Partial<LicenseInterface> | string;
   };
   _uplinks: {};
 }