Add Optional Strict Input Checking to u8aToU8a (#1994)

* fix: add error handling for null and undefined inputs in u8aToU8a function

* fix: update u8aToU8a function to handle null/undefined inputs with strict checking

* docs: update documentation for u8aToU8a

packages/util/src/u8a/toU8a.spec.ts

@@ -20,23 +20,29 @@ const TESTS: [input: U8aLike | null | undefined, output: Uint8Array][] = [
 
 describe('u8aToU8a', (): void => {
   it('returns an empty Uint8Array when null/undefined/"" provided', (): void => {
-    expect(
-      u8aToU8a(null)
-    ).toHaveLength(0);
+    expect(u8aToU8a(null)).toHaveLength(0);
     expect(
       u8aToU8a()
     ).toHaveLength(0);
     expect(
       u8aToU8a('')
     ).toHaveLength(0);
+    expect(
+      u8aToU8a('')
+    ).toEqual(new Uint8Array());
+  });
+
+  it('Throw error on null/undefined values on strict checking', () => {
+    expect(() => u8aToU8a(undefined, true)).toThrow('u8aToU8a: Expected non-null, non-undefined value');
+    expect(() => u8aToU8a(null, true)).toThrow('u8aToU8a: Expected non-null, non-undefined value');
   });
 
   it('returns a Uint8Array as-is (u8a input)', (): void => {
     const input = new Uint8Array([128, 0, 10]);
 
     expect(
-      u8aToU8a(input) === input
-    ).toEqual(true);
+      u8aToU8a(input)
+    ).toEqual(input);
   });
 
   describe('conversion tests', (): void => {

packages/util/src/u8a/toU8a.ts

@@ -14,6 +14,8 @@ import { stringToU8a } from '../string/toU8a.js';
  * @summary Creates a Uint8Array value from a Uint8Array, Buffer, string or hex input.
  * @description
  * `null` or `undefined` inputs returns a `[]` result, Uint8Array values returns the value, hex strings returns a Uint8Array representation.
+ * If `strict` is true, `null` or `undefined` will throw an error instead of returning an empty array.
+ * Supports input types: Uint8Array, Buffer, hex string, string, or number array.
  * @example
  * <BR>
  *
@@ -24,7 +26,11 @@ import { stringToU8a } from '../string/toU8a.js';
  * u8aToU8a(0x1234); // => Uint8Array([0x12, 0x34])
  * ```
  */
-export function u8aToU8a (value?: U8aLike | null): Uint8Array {
+export function u8aToU8a (value?: U8aLike | null, strict = false): Uint8Array {
+  if (strict && (value === null || value === undefined)) {
+    throw new Error('u8aToU8a: Expected non-null, non-undefined value');
+  }
+
   return isU8a(value)
     // NOTE isBuffer needs to go here since it actually extends
     // Uint8Array on Node.js environments, so all Buffer are Uint8Array,