chore: add fallback option

Author: technote-space

__tests__/utils1.test.ts

@@ -214,6 +214,12 @@ describe('normalizeVersion', () => {
     expect(normalizeVersion('abc')).toBeUndefined();
     expect(normalizeVersion('test/v1.2.3')).toBeUndefined();
   });
+
+  it('should return fallback', () => {
+    expect(normalizeVersion('', {fallback: ''})).toBe('');
+    expect(normalizeVersion('', {fallback: null})).toBe(null);
+    expect(normalizeVersion('', {fallback: 'abc'})).toBe('abc');
+  });
 });
 
 describe('isValidSemanticVersioning', () => {

src/utils.ts

@@ -63,10 +63,10 @@ export const parseVersion = (version: string, options?: { fill?: boolean; cut?:
   };
 };
 
-export const normalizeVersion = (version: string, options?: { fill?: boolean; cut?: boolean; slice?: number; length?: number; onlyCore?: boolean; }): string | undefined => {
+export const normalizeVersion = (version: string, options?: { fill?: boolean; cut?: boolean; slice?: number; length?: number; onlyCore?: boolean; fallback?: string | null }): string | undefined | null => {
   const parsed = parseVersion(version, options);
   if (!parsed) {
-    return undefined;
+    return options?.fallback;
   }
 
   if (options?.onlyCore) {