Javascript Fetch does not provide my content in Response message-CodePudding

I am struggling with the Response of the Javascript fetch() method. What is my objective: a) to send multiple lines to the backend to save those to a database and b) get a guid in return for further processing. I succeed in objective a (save to database), but the return message fails to materialise. Response.ok is true, but no message is part of the return message. What should I do to accomplish this?

My javascript is:

function saveAll(event) {
event.preventDefault();

var newDeelnemers = new Array();
var lijst = document.querySelectorAll('#tblDeelnemers tbody tr')   

lijst.forEach(function (dnmr) {
    var row = dnmr;
    var deelnemer = {};
    var nDnmr = row.children;
    //deelnemer.Id = nDnmr[0].innerHTML;
    deelnemer.FamilielidFirstName = nDnmr[0].innerHTML;
    deelnemer.Achternaam = nDnmr[1].innerHTML;
    deelnemer.DOB = nDnmr[2].innerHTML;
    deelnemer.Programma = nDnmr[3].innerHTML;
    deelnemer.EetMee = nDnmr[4].firstChild.checked;
    deelnemer.Dieet = nDnmr[5].innerHTML;
    deelnemer.Bedrag = nDnmr[6].innerHTML;
    newDeelnemers.push(deelnemer);
});

fetch("/Familiedag/Registreer", {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
    },
    body: JSON.stringify(newDeelnemers)
}).then(function (response) {
    console.log('eerste keer: '   response);
    if (response.ok) {
        alert('De registratie is gelukt');
        //redirect("/Familiedag/RegistreerConfirm?")
    }
});   
}

The controller

[HttpPost]
    public IActionResult Registreer([FromBody] List<FdDeelnemer> newDeelnemers)       
    {
        if (newDeelnemers.Count == 0)
        {
            return null;
        }

        Guid registratieGuid = Guid.NewGuid();

        foreach (var ndn in newDeelnemers)
        {
            FdDeelnemer VM = new FdDeelnemer();
            VM.RegistratieGuid = registratieGuid;                
            VM.FamilielidFirstName = ndn.FamilielidFirstName;
            VM.Achternaam = ndn.Achternaam;
            VM.EetMee = ndn.EetMee;
            VM.Dieet = ndn.Dieet;
            VM.Programma = ndn.Programma;
            VM.DOB = ndn.DOB;
            VM.Bedrag = ndn.Bedrag;
            VM.CreatedBy = User.Identity.Name;
            VM.CreatedOn = DateTime.UtcNow;
            _context.Add(VM);
        }
        
        Guid geregistreerdeDeelnemers = registratieGuid;
        return Json(geregistreerdeDeelnemers);            
    }

CodePudding user response：

add another .then that return the json

fetch("/echo/json/", {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "tes": "data"
  })
}).then(function(response) {
  return response.json();
}).then(function(json) {
  console.log('eerste keer: ', json);
  alert('De registratie is gelukt');
  //redirect("/Familiedag/RegistreerConfirm?")
});

CodePudding user response：

You can try to return it like that:

return Json(new { AnythingYouWant = geregistreerdeDeelnemers });