Isomorphic Fetch post body data empty solution

Isomorphic Fetch post body data empty solution

Client: 
fetching with headers: 
{ "Content-Type": "application/json" }
Stringifying JSON:
body: JSON.stringify(data)

Server: add:
app.use((req, res, next) => {
	res.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
	next();
});

app.use(require("body-parser").json())
app.use(bodyParser.urlencoded({ extended: true }));

Eg.

Client: 
let data = { something: 'something else' }
fetch(`/api/register`, {
        method: 'POST',
				body: JSON.stringify(data),
				headers: { "Content-Type": "application/json" }
      })
			.then((res) => {
				res.json().then(res=>{
					console.log('res', res)
				})
      })
      .catch(err=>{
        console.error('err', err)
      })
      
Bonus tidbit:
To return/res json you need to set this header:
router.post('/register', async (req, res) => {
	res.setHeader('Content-Type', 'application/json');
	res.json({etc: 'etc...'})
// etc....
})

And fetch requires res.json().then(res=>{}) format for some dumb af reason