I'm making a little database using mongodb and nodejs, I want to Update a field but I have this error, the code is, the name of the model is "ListaSalas":

router.post('/updatesala', function(peticion, responsep){
  var password = peticion.body.password;
  var url = peticion.body.url;

  ListaSalas.findOne({'url': url}, function (err, respuesta) {
    var PassBusca = respuesta.password;
    if(PassBusca){
      responsep.writeHead(200, {"Content-Type": "text/html"});
      responsep.write("passwordmal");
      responsep.end();
    }else{
      ListaSalas.update({url: url}, {password: password});
      responsep.writeHead(200, {"Content-Type": "text/html"});
      responsep.write("passwordok");
      responsep.end();
    }
  });

Does anybody know where my mistake is please? Thank you

I'm making a little database using mongodb and nodejs, I want to Update a field but I have this error, the code is, the name of the model is "ListaSalas":

router.post('/updatesala', function(peticion, responsep){
  var password = peticion.body.password;
  var url = peticion.body.url;

  ListaSalas.findOne({'url': url}, function (err, respuesta) {
    var PassBusca = respuesta.password;
    if(PassBusca){
      responsep.writeHead(200, {"Content-Type": "text/html"});
      responsep.write("passwordmal");
      responsep.end();
    }else{
      ListaSalas.update({url: url}, {password: password});
      responsep.writeHead(200, {"Content-Type": "text/html"});
      responsep.write("passwordok");
      responsep.end();
    }
  });

Does anybody know where my mistake is please? Thank you

• javascript
• node.js
• mongodb

3 Answers 3

The issue is on the result returned from the findOne() method, if there is no match then respuesta is null hence the error

Cannot read property 'password' of null

To get around this, use the updateOne() method directly and in the callback check whether the document has been modified:

router.post('/updatesala', function(peticion, responsep){
    var password = peticion.body.password;
    var url = peticion.body.url;

    ListaSalas.updateOne({'url': url}, {'password': password}, function (err, result) {
        if (err) return err;
        var PassBusca = result.result.n;
        var pwd = PassBusca ? "passwordmal": "passwordok";
        responsep.writeHead(200, {"Content-Type": "text/html"});
        responsep.write(pwd);
        responsep.end();        
    });
});

You are not checking if there is an error or not.

router.post('/updatesala', function(peticion, responsep){
  var password = peticion.body.password;
  var url = peticion.body.url;

  ListaSalas.findOne({'url': url}, function (err, respuesta) {
    if (err) return err;
    var PassBusca = respuesta.password;
    if(PassBusca){
      responsep.writeHead(200, {"Content-Type": "text/html"});
      responsep.write("passwordmal");
      responsep.end();
    }else{
      ListaSalas.update({url: url}, {password: password});
      responsep.writeHead(200, {"Content-Type": "text/html"});
      responsep.write("passwordok");
      responsep.end();
    }
  });
  ...

After checking the answers I could change the code, thanks to chridam's idea I used the method directly, instead of updateOne() it was update(), and in the database I put a default value in the password field ("password"), at the end the code is:

router.post('/updatesala', function(peticion, responsep){
  var password = peticion.body.password;
  var url = peticion.body.url;
  ListaSalas.findOne({'url': url}, function (err, respuesta) {
  var para = respuesta.password;
  if (para=="password"){
    ListaSalas.update({'url': url}, {'password': password},function (err, result) {
        if (err) return err;
        });
    responsep.writeHead(200, {"Content-Type": "text/html"});
    responsep.write('passwordok');
    responsep.end();
  }else{
    responsep.writeHead(200, {"Content-Type": "text/html"});
    responsep.write('passwordmal');
    responsep.end();}
  });
});