fix: minor adjustments & add test suite

Author: tada5hi

packages/jsonwebtoken/__tests__/jsonwebtoken.spec.ts

@@ -4,7 +4,7 @@ import { join } from 'node:path'
 import test from 'ava'
 import { decode as nodeJwtDecode } from 'jsonwebtoken'
 
-import { Algorithm, sign, signSync, verifySync, verify } from '../index.js'
+import { Algorithm, sign, signSync, verifySync, verify, decodeHeader } from '../index.js'
 
 const getUtcTimestamp = () => Math.floor(new Date().getTime() / 1000)
 const oneDayInSeconds = 86400
@@ -30,6 +30,20 @@ test('signSync and sign (async) should produce the same result', async (t) => {
   t.truthy(nodeJwtDecode(resAsync))
 })
 
+test('should decode header', async (t) => {
+  const data = {
+    id: 'f81d4fae-7dec-11d0-a765-00a0c91e6bf6',
+  }
+  const claims = { data, exp: getUtcTimestamp() + oneDayInSeconds }
+  const secretKey = 'secret'
+  const headers = { algorithm: Algorithm.HS384 }
+
+  const token = await sign(claims, secretKey, headers)
+
+  const header = decodeHeader(token);
+  t.is(header.algorithm, Algorithm.HS384);
+})
+
 test('verify should return the decoded claims', async (t) => {
   const data = {
     id: 'f81d4fae-7dec-11d0-a765-00a0c91e6bf6',

packages/jsonwebtoken/index.d.ts

@@ -160,3 +160,4 @@ export function verify(token: string, key: string | Buffer, validation?: Validat
 
 export function verifySync(token: string, key: string | Buffer, validation?: Validation | undefined | null): Claims
 
+export function decodeHeader(token: string) : Header;

packages/jsonwebtoken/src/decode.rs

@@ -1,4 +1,3 @@
-use napi::bindgen_prelude::*;
 use napi_derive::napi;
 
 use crate::header::Header;

packages/jsonwebtoken/src/header.rs

@@ -73,11 +73,11 @@ impl From<&Header> for jsonwebtoken::Header {
   }
 }
 
-impl From<jsonwebtoken::Header> for Header {
+impl From<&jsonwebtoken::Header> for Header {
   #[inline]
   fn from(value: &jsonwebtoken::Header) -> Header {
     Header {
-      algorithm: value.alg.into(),
+      algorithm: value.alg.clone(),
       content_type: value.cty.clone(),
       json_key_url: value.jku.clone(),
       key_id: value.kid.clone(),