feat: add options.type

README.md

@@ -147,6 +147,7 @@ As mentioned in [this comment](https://github.com/auth0/node-jsonwebtoken/issues
   > * rsa - ['RS256', 'RS384', 'RS512']
   > * ec - ['ES256', 'ES384', 'ES512']
   > * default - ['RS256', 'RS384', 'RS512']
+* `type`: if you want to check token type (`typ`), provide a string value here (e.g. 'JWT', 'at+jwt').
 * `audience`: if you want to check audience (`aud`), provide a value here. The audience can be checked against a string, a regular expression or a list of strings and/or regular expressions. 
   > Eg: `"urn:foo"`, `/urn:f[o]{2}/`, `[/urn:f[o]{2}/, "urn:bar"]`
 * `complete`: return an object with the decoded `{ payload, header, signature }` instead of only the usual content of the payload.
@@ -191,6 +192,12 @@ jwt.verify(token, cert, function(err, decoded) {
   console.log(decoded.foo) // bar
 });
 
+// verify type
+var cert = fs.readFileSync('public.pem');  // get public key
+jwt.verify(token, cert, { type: 'at+jwt' }, function(err, decoded) {
+  // if typ mismatch, err == invalid type
+});
+
 // verify audience
 var cert = fs.readFileSync('public.pem');  // get public key
 jwt.verify(token, cert, { audience: 'urn:foo' }, function(err, decoded) {
@@ -314,6 +321,8 @@ Error object:
   * 'jwt issuer invalid. expected: [OPTIONS ISSUER]'
   * 'jwt id invalid. expected: [OPTIONS JWT ID]'
   * 'jwt subject invalid. expected: [OPTIONS SUBJECT]'
+  * 'jwt type invalid. expected: [OPTIONS TYPE]'
+
 
 ```js
 jwt.verify(token, 'shhhhh', function(err, decoded) {

test/option-complete.test.js

@@ -10,7 +10,7 @@ describe('complete option', function () {
   const secret = fs.readFileSync(path.join(__dirname, 'priv.pem'));
   const pub = fs.readFileSync(path.join(__dirname, 'pub.pem'));
 
-  const header = { alg: 'RS256' };
+  const header = { alg: 'RS256', typ: 'JWT' };
   const payload = { iat: Math.floor(Date.now() / 1000 ) };
   const signed = jws.sign({ header, payload, secret, encoding: 'utf8' });
   const signature = jws.decode(signed).signature;
@@ -26,6 +26,7 @@ describe('complete option', function () {
         testUtils.asyncCheck(done, () => {
           expect(err).to.be.null;
           expect(decoded.header).to.have.property('alg', header.alg);
+          expect(decoded.header).to.have.property('typ', header.typ);
           expect(decoded.payload).to.have.property('iat', payload.iat);
           expect(decoded).to.have.property('signature', signature);
         });

test/verify.tests.js

@@ -268,6 +268,32 @@ describe('verify', function() {
     });
   });
 
+  describe('option: type', function () {
+    // { "alg": "HS256", "typ": "JWT" } { "foo": "bar", "iat": 1437018582, "exp": 1437018592 }
+    const token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJpYXQiOjE0MzcwMTg1ODIsImV4cCI6MTQzNzAxODU5Mn0.3aR3vocmgRpG05rsI9MpR6z2T_BGtMQaPq2YR6QaroU';
+    let clock;
+    const key = 'key';
+
+    beforeEach(function () {
+      // iat + 1s
+      try { clock = sinon.useFakeTimers(1437018583000); } catch (e) {}
+    });
+
+    afterEach(function () {
+      try { clock.restore(); } catch (e) {}
+    });
+
+    it('should pass if token.header.typ is equal to options.type', function () {
+      const options = { type: 'JWT' };
+      expect(function() { jwt.verify(token, key, options) }).to.not.throw();
+    });
+
+    it('should error if token.header.typ is not equal to options.type', function () {
+      const options = { type: 'at+jwt' };
+      expect(function() { jwt.verify(token, key, options) }).to.throw('jwt type invalid. expected: at+jwt');
+    });
+  });
+
   describe('when verifying a token with an unsupported public key type', function () {
     it('should throw an error', function() {
       const token = 'eyJhbGciOiJSUzI1NiJ9.eyJpYXQiOjE2Njk5OTAwMDN9.YdjFWJtPg_9nccMnTfQyesWQ0UX-GsWrfCGit_HqjeIkNjoV6dkAJ8AtbnVEhA4oxwqSXx6ilMOfHEjmMlPtyyyVKkWKQHcIWYnqPbNSEv8a7Men8KhJTIWb4sf5YbhgSCpNvU_VIZjLO1Z0PzzgmEikp0vYbxZFAbCAlZCvUlcIc-kdjIRCnDJe0BBrYRxNLEJtYsf7D1yFIFIqw8-VP87yZdExA4eHsTaE84SgnL24ZK5h5UooDx-IRNd_rrMyio8kNy63grVxCWOtkXZ26iZk6v-HMsnBqxvUwR6-8wfaWrcpADkyUO1q3SNsoTdwtflbvfwgjo3uve0IvIzHMw';

verify.js

@@ -83,6 +83,16 @@ module.exports = function (jwtString, secretOrPublicKey, options, callback) {
   }
 
   const header = decodedToken.header;
+
+  if (options.type) {
+    const invalid_type =
+        (typeof options.type === 'string' && header.typ !== options.type);
+
+    if (invalid_type) {
+      return done(new JsonWebTokenError('jwt type invalid. expected: ' + options.type));
+    }
+  }
+
   let getSecret;
 
   if(typeof secretOrPublicKey === 'function') {