Fix normalize for empty strings (#315)

* fix: normalize should also work with empty strings

* test: add test for empty string normalization

src/utils.test.ts

@@ -124,6 +124,12 @@ describe('normalize', function () {
     expect(result).toBe('0x');
   });
 
+  it('should normalize an empty string to 0x', function () {
+    const initial = '';
+    const result = normalize(initial);
+    expect(result).toBe('0x');
+  });
+
   // TODO: Add validation to disallow null.
   it('should return undefined if given null', function () {
     const initial = null;

src/utils.ts

@@ -103,7 +103,7 @@ export function recoverPublicKey(
  * @returns The normalized value.
  */
 export function normalize(input: number | string): string | undefined {
-  if (!input) {
+  if (isNullish(input)) {
     return undefined;
   }