Content-Type header needs to be one as defined by IANA team

[prayagupa]

app.get('/test', (rq, res) => {                                                                        
 res.status(200).header('Content-Type', 'rubbish').send({'data': 'test'})                              
});   

λ node app.js 
adding session
Express server listening on port 3000
GET /test 500 2.473 ms - 1769
TypeError: invalid media type
    at Object.parse (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/content-type/index.js:126:11)
    at setCharset (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/express/lib/utils.js:256:28)
    at ServerResponse.send (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/express/lib/response.js:170:32)
    at ServerResponse.json (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/express/lib/response.js:267:15)
    at ServerResponse.send (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/express/lib/response.js:158:21)
    at app.get (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/app.js:42:52)
    at Layer.handle [as handle_request] (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/express/lib/router/layer.js:95:5)
    at next (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/express/lib/router/route.js:137:13)
    at Route.dispatch (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/express/lib/router/route.js:112:3)
    at Layer.handle [as handle_request] (/Users/a1353612/soundofmusic/compile1010/nodejs-microservice/onlywallet-backend/node_modules/express/lib/router/layer.js:95:5)
err adding session: Error: Timed out while trying to establish connection
err setting new session: Error: Timed out while trying to establish connection

https://stackoverflow.com/questions/23714383/what-are-all-the-possible-values-for-http-content-type-header