sequelize error: Unhandled rejection TypeError: expecting an array or an iterable object but got [object Null]

Question

I'm trying to use findOne from sequelize in my model, but I'm receiving this error The table that the model is referencing is empty, how to handle this?

Unhandled rejection TypeError: expecting an array or an iterable object but got [object Null]

This is my code:

app.get('/test/models', function(req, res) {

        var values = { 
            where: { user_id: 7 } 
        };

        MercadoLibre.findOne(values)
        .spread(function(err, meli) {

            console.log(err);

            if (typeof meli !== null) {
                console.log("undefined");
            } else {
                console.log(meli);    
            }

            res.redirect('/dashboard');
        });
    });

How can I fix this?

Answer 1

There are a few bugs in your code

• You should be handling a Promise.reject() result from MercadoLibre.findOne().

• You should get the results of findOne() using .then(), not .spread()

  .then(function(resolve)).catch(function(reject))

  • You can handle resolve() and reject() in a single thenable, but the format is:

    .then(function(resolve), function(reject))

• You are checking for null incorrectly (no need for typeof), and your code will always return true (even if meli is undefined, so will the typeof)

  typeof meli !== null

app.get('/test/models', function(req, res) {
  var values = { 
    where: { user_id: 7 } 
  };

  MercadoLibre.findOne(values)
  .then(function(result) {
    // just check for false-y
    if (!result) {
      console.log('Nothing was returned!')
    }
    // redirect to the route you want
    res.redirect('/dashboard');
  })
  .catch(function(err) {
    // catch any errors
    console.log('Error, do some kind of redirect?!', err);
  });
});