Keep previous Content-Type for res.jsonp

backport of commit be997fd654

History.md

@@ -1,6 +1,7 @@
 3.x
 ===
 
+ * keep previous `Content-Type` for `res.jsonp`
  * update connect to 2.17.1
    - fix `res.charset` appending charset when `content-type` has one
    - deps: express-session@1.2.0

lib/response.js

@@ -248,7 +248,7 @@ res.jsonp = function(obj){
 
   // content-type
   this.charset = this.charset || 'utf-8';
-  this.set('Content-Type', 'application/json');
+  this.get('Content-Type') || this.set('Content-Type', 'application/json');
 
   // fixup callback
   if (Array.isArray(callback)) {

test/res.jsonp.js

@@ -334,4 +334,22 @@ describe('res', function(){
       })
     })
   })
+
+  it('should not override previous Content-Types', function(done){
+    var app = express();
+
+    app.get('/', function(req, res){
+      res.type('application/vnd.example+json');
+      res.jsonp({ hello: 'world' });
+    });
+
+    request(app)
+    .get('/')
+    .end(function(err, res){
+      res.statusCode.should.equal(200);
+      res.headers.should.have.property('content-type', 'application/vnd.example+json');
+      res.text.should.equal('{"hello":"world"}');
+      done();
+    })
+  })
 })