chore: add explicit types

Signed-off-by: Okiki <okikio.dev@gmail.com>

byte_methods.ts

@@ -26,7 +26,7 @@ import {
  * @param byte - The lead byte of a UTF-8 character.
  * @returns The number of bytes in a Uint8Array required to represent the UTF-8 character (the number of bytes ranges from 1 to 4).
  */
-export function getByteLength(byte: number) {
+export function getByteLength(byte: number): number {
   return (
     byte < LEAD_FOR_1B ? 1 :
     LEAD_FOR_2B === (LEAD_FOR_3B & byte) ? 2 :
@@ -54,7 +54,7 @@ export function getByteLength(byte: number) {
  * @param [bytes] - An array of length `byteLength` bytes that make up the UTF-8 character.
  * @returns The Unicode code point of the UTF-8 character.
  */
-export function bytesToCodePoint(byteLength: number, [byte1, byte2, byte3, byte4]: number[]) {
+export function bytesToCodePoint(byteLength: number, [byte1, byte2, byte3, byte4]: number[]): number {
   return (
     // 1-byte UTF-8 sequence
     byteLength === 1 ?
@@ -131,7 +131,7 @@ export function bytesToCodePointFromBuffer<T extends number = number>(
  * @param index - The position in the string to extract the code point from.
  * @returns A number represent the code point in UTF-16 code units.
  */
-export function codePointAt(str: string, index: number) {
+export function codePointAt(str: string, index: number): number {
   const size = str.length;
 
   // Account for out-of-bounds indices:

iterable.ts

@@ -7,7 +7,7 @@
  * 
  * @param stream ReadableStream to convert into async iterable
  */
-export async function* getIterableStream<T = Uint8Array>(stream: ReadableStream<T>) {
+export async function* getIterableStream<T = Uint8Array>(stream: ReadableStream<T>): AsyncIterable<T> {
   const reader = stream.getReader();
   try {
     while (true) {

mod.ts

@@ -23,7 +23,7 @@
  */
 export async function* asCodePointsIterator<T extends Uint8Array>(
   iterable: AsyncIterable<T> | Iterable<T>
-) {
+): AsyncIterable<number> {
   const utf8Decoder = new TextDecoder("utf-8");
 
   // Create an async iterator from the source (works for both async and sync iterables).
@@ -68,7 +68,7 @@ export async function* asCodePointsIterator<T extends Uint8Array>(
  */
 export async function asCodePointsArray<T extends Uint8Array>(
   iterable: AsyncIterable<T> | Iterable<T>
-) {
+): Promise<number> {
   const arr: number[] = [];
   const utf8Decoder = new TextDecoder("utf-8");