feat: add hex

Author: Bekacru

README.md

@@ -20,6 +20,7 @@ utilities provided by `@better-auth/utils`:
 | [**RSA**](#rsa)   | Perform encryption, decryption, signing, and verification with RSA keys. |
 | [**ECDSA**](#ecdsa) | Perform signing and verification with ECDSA keys. |
 | [**Base64**](#base64) | Encode and decode data in base64 format.          |
+| [**Hex**](#hex)   | Encode and decode data in hexadecimal format.      |
 | [**OTP**](#otp) | Generate and verify one-time passwords.            |
 | [**Cookies**](#cookies) | Parse, serialize, and manage HTTP cookies.         |
 
@@ -254,6 +255,28 @@ const decodedData = await base64.decode(encodedData);
 It automatically detects if the input is URL-safe and includes padding characters.
 
 
+## Hex
+
+Hex utilities provide a simple interface to encode and decode data in hexadecimal format.
+
+### Encoding
+
+Encode data in hexadecimal format. Input can be a string, `ArrayBuffer`, or `TypedArray`.
+
+```ts
+import { hex } from "@better-auth/utils/hex";
+
+const encodedData = hex.encode("Data to encode");
+```
+
+### Decoding
+
+Decode hexadecimal-encoded data. Input can be a string or `ArrayBuffer`.
+
+```ts
+const decodedData = hex.decode(encodedData);
+```
+
 ## OTP
 
 The OTP utility provides a simple and secure way to generate and verify one-time passwords (OTPs), commonly used in multi-factor authentication (MFA) systems. It includes support for both HOTP (HMAC-based One-Time Password) and TOTP (Time-based One-Time Password) standards.

package.json

@@ -55,6 +55,10 @@
       "import": "./dist/ecdsa.mjs",
       "require": "./dist/ecdsa.cjs"
     },
+    "./hex": {
+      "import": "./dist/hex.mjs",
+      "require": "./dist/hex.cjs"
+    },
     "./hmac": {
       "import": "./dist/hmac.mjs",
       "require": "./dist/hmac.cjs"

src/hex.test.ts

@@ -0,0 +1,64 @@
+import { describe, it, expect } from 'vitest';
+import { hex } from './hex';
+
+describe('hex', () => {
+    describe('encode', () => {
+        it('should encode a string to hexadecimal', () => {
+            const input = "Hello, World!";
+            const expected = "48656c6c6f2c20576f726c6421";
+            expect(hex.encode(input)).toBe(expected);
+        });
+
+        it('should encode an ArrayBuffer to hexadecimal', () => {
+            const input = new TextEncoder().encode("Hello").buffer;
+            const expected = "48656c6c6f";
+            expect(hex.encode(input)).toBe(expected);
+        });
+
+        it('should encode a TypedArray to hexadecimal', () => {
+            const input = new Uint8Array([72, 101, 108, 108, 111]);
+            const expected = "48656c6c6f";
+            expect(hex.encode(input)).toBe(expected);
+        });
+    });
+
+    describe('decode', () => {
+        it('should decode a hexadecimal string to its original value', () => {
+            const input = "48656c6c6f2c20576f726c6421";
+            const expected = "Hello, World!";
+            expect(hex.decode(input)).toBe(expected);
+        });
+
+        it('should handle decoding of a hexadecimal string to binary data', () => {
+            const input = "48656c6c6f";
+            const expected = "Hello";
+            expect(hex.decode(input)).toBe(expected);
+        });
+
+        it('should throw an error for an odd-length string', () => {
+            const input = "123";
+            expect(() => hex.decode(input)).toThrow(Error);
+        });
+
+        it('should throw an error for a non-hexadecimal string', () => {
+            const input = "zzzz";
+            expect(() => hex.decode(input)).toThrow(Error);
+        });
+    });
+
+    describe('round-trip tests', () => {
+        it('should return the original string after encoding and decoding', () => {
+            const input = "Hello, Hex!";
+            const encoded = hex.encode(input);
+            const decoded = hex.decode(encoded);
+            expect(decoded).toBe(input);
+        });
+
+        it('should handle empty strings', () => {
+            const input = "";
+            const encoded = hex.encode(input);
+            const decoded = hex.decode(encoded);
+            expect(decoded).toBe(input);
+        });
+    });
+});

src/hex.ts

@@ -0,0 +1,37 @@
+import type { TypedArray } from "./type";
+
+
+const hexadecimal = "0123456789abcdef";
+export const hex = {
+    encode: (data:
+        string | ArrayBuffer | TypedArray) => {
+        if (typeof data === "string") {
+            data = new TextEncoder().encode(data);
+        }
+        if (data.byteLength === 0) {
+            return "";
+        }
+        const buffer = new Uint8Array(data);
+        let result = "";
+        for (const byte of buffer) {
+            result += byte.toString(16).padStart(2, "0");
+        }
+        return result;
+    },
+    decode: (data: string) => {
+        if (!data) {
+            return "";
+        }
+        if (data.length % 2 !== 0) {
+            throw new Error("Invalid hexadecimal string");
+        }
+        if (!new RegExp(`^[${hexadecimal}]+$`).test(data)) {
+            throw new Error("Invalid hexadecimal string");
+        }
+        const result = new Uint8Array(data.length / 2);
+        for (let i = 0; i < data.length; i += 2) {
+            result[i / 2] = parseInt(data.slice(i, i + 2), 16);
+        }
+        return new TextDecoder().decode(result);
+    }
+}