angularjs - Getting error "Cant set headers after they are sent" when trying to upload image and user data to mongoDB -

i using node, express, mongo , angular make simple app. have form user can insert data , upload image. image upload use ng-file-upload. using multiparty form data. here api upload of image server folder , save , entry in mongdb of user data along filename.

router.route('/upload/image')     .post(function(req, res){     var form = new multiparty.form();     form.parse(req, function(err, fields, files) {         console.log(files);         console.log(fields);         var file = files.file[0];         var contenttype = file.headers['content-type'];         var tmppath = file.path;         var extindex = tmppath.lastindexof('.');         var extension = (extindex < 0) ? '' : tmppath.substr(extindex);         // uuid generating unique filenames.         var filename = uuid.v4() + extension;         var destpath = './public/img/' + filename;          // server side file type checker.         if (contenttype !== 'image/png' && contenttype !== 'image/jpeg' && contenttype !== 'image/jpg') {             fs.unlink(tmppath);             return res.status(400).send('unsupported file type.');         }          fs.rename(tmppath, destpath, function(err) {             if (err) {                 return res.status(400).send('image not saved:');             }             return res.json(destpath);         });          var user = new user();         user.firstname = fields.firstname;         user.lastname = fields.lastname;         user.email = fields.email;         user.numofcups = fields.numofcups;         user.currentbalance = fields.currentbalance;         user.totalnumofcups = fields.numofcups;         user.totalmoneyspent = fields.currentbalance;         user.photo = destpath;          user.save(function(err, user){             if(err){                 return res.send(500, err);             }             return res.json(user);         });     }); }); 

when save user data in ui copies file server folder not save data mongodb , throw error - "cant set headers after sent". it has res.json being called twice, how solve this? pointers appreciated.

you cannot send multiples responses.

fix: remove return res.json(destpath); , put code creation of user saving entity, in place of return res.json(destpath);