feat: add jwt utils

.changeset/silent-moons-boil.md

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+---
+'@storipress/karbon-utils': minor
+---
+
+feat: add jwt utils

packages/karbon-utils/src/__tests__/jwt.spec.ts

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+import '../crypto-polyfill'
+import { describe, expect } from 'vitest'
+import { fc, it } from '@fast-check/vitest'
+import { createEncryptJWT, decryptJWT, textToUint8Array, uint8ArrayToText } from '../jwt'
+
+describe('createEncryptJWT', () => {
+  // Returns an encrypted JWT string when given a valid key and plaintext
+  it('should return an encrypted JWT string when given a valid key and plaintext', async () => {
+    const key = new Uint8Array(32)
+    const plaintext = 'Hello, world!'
+    const result = await createEncryptJWT(key, plaintext)
+    expect(typeof result).toBe('string')
+  })
+
+  // Returns an error when given a key of incorrect length
+  it('should return an error when given a key of incorrect length', async () => {
+    const key = new Uint8Array(16)
+    const plaintext = 'Hello, world!'
+    await expect(createEncryptJWT(key, plaintext)).rejects.toThrowError()
+  })
+})
+
+describe('createEncryptJWT & decryptJWT', () => {
+  it.prop({ plaintext: fc.string(), key: fc.uint8Array({ minLength: 32, maxLength: 32 }) })(
+    'can encrypt and decrypt',
+    async ({ plaintext, key }) => {
+      const result = await createEncryptJWT(key, plaintext)
+
+      expect(typeof result).toBe('string')
+
+      expect(result).not.toBe(plaintext)
+
+      const decrypted = await decryptJWT(key, result)
+
+      expect(decrypted).toBe(plaintext)
+    },
+  )
+})
+
+describe('textToUint8Array & uint8ArrayToText', () => {
+  it.prop({ text: fc.string() })('can convert text to and from uint8array', ({ text }) => {
+    const array = textToUint8Array(text)
+    const result = uint8ArrayToText(array)
+    expect(result).toBe(text)
+  })
+})

packages/karbon-utils/src/jwt.ts

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+import { CompactEncrypt, compactDecrypt } from '@storipress/jose-browser'
+
+export async function createEncryptJWT(key: Uint8Array, plaintext: string) {
+  const compactEncrypt = new CompactEncrypt(textToUint8Array(plaintext)).setProtectedHeader({
+    enc: 'A256GCM',
+    alg: 'dir',
+  })
+  return await compactEncrypt.encrypt(key)
+}
+
+export async function decryptJWT(key: Uint8Array, jwt: string) {
+  const { plaintext } = await compactDecrypt(jwt, key)
+  return uint8ArrayToText(plaintext)
+}
+
+export function textToUint8Array(text: string) {
+  const encoder = new TextEncoder()
+  return encoder.encode(text)
+}
+
+export function uint8ArrayToText(array: Uint8Array) {
+  const decoder = new TextDecoder()
+  return decoder.decode(array)
+}