fix(#142): update normalizeSync input type to string only

README.md

@@ -85,14 +85,14 @@ await normalize('söme stüff with áccènts'); // 'some stuff with accents'
 
 ## API Reference
 
-### normalize([input])
+### `normalize([input])`
 
-- `input` <?[string][string-mdn-url]> Optional input string that contains accents/ diacritics.
+- `input` <[string][string-mdn-url]> Input string that contains accents/diacritics.
 - returns: <[Promise][promise-mdn-url]<[string][string-mdn-url]>> Promise which resolves with normalized input string.
 
 This method normalizes any accents/ diacritics found in a given input string and output a normalized string as a result.
 
-### normalizeSync([input])
+### `normalizeSync([input])`
 
 This methods works the same as `normalize([input])` except that this is the synchronous version.
 

src/normalize-sync.ts

@@ -1,6 +1,6 @@
 import { diacritics } from './diacritics.js';
 
-export function normalizeSync(input?: string | null): string {
+export function normalizeSync(input: string): string {
   if ('string' !== typeof(input)) {
     throw new TypeError(`Expected 'input' to be of type string, but received '${input}'`);
   }
@@ -28,6 +28,5 @@ export function normalizeSync(input?: string | null): string {
     );
 
     return normalized == null ? s : normalized.letter;
-    // return null == normalized ? s : normalized.letter;
   });
 }

src/normalize.ts

@@ -1,5 +1,5 @@
 import { normalizeSync } from './normalize-sync.js';
 
-export async function normalize(input?: string | null): Promise<string> {
+export async function normalize(input: string): Promise<string> {
   return normalizeSync(input);
 }

src/tests/error.test.ts

@@ -8,6 +8,7 @@ describe(normalize.name, () => {
     undefined,
   ])('throws error when calling normalize(%s)', async (testInput) => {
     try {
+      // @ts-expect-error - Intentionally passing invalid input
       await normalize(testInput);
     } catch (error) {
       expect(error).toEqual(