Returning values of a fetch - backbone.js

Question

Please look at the code below. It's a Backbone/Parse code that uses some underscore features.
I'm trying to iterate over an Parse class to retrieve "firstName" attributes of all objects in that class.
I have 2 issues with it.
The first one, as indicated with the comment, is that it correctly retrieves the first names, but it duplicates them. So if there are 5 objects, it will retrieve 5 firstName * 5. There is an iteration problem here. This is shown with the console log.
Second problem, is that I try to push firstName values into an array, then return it, so I can use the values later in code using the testt variable. But checking the testt content with a console log sends a message instead of the firstname lists.
Do you see anyway how to fix this code ?
var DoopizCollection = Parse.Collection.extend({
model: Subscribers
}
);
var doopizlist = new DoopizCollection();
var testt;
testt = doopizlist.fetch({
success: function(doopizlist) {
var results = [];
doopizlist.each(function(object) {
results.push(doopizlist.pluck('firstName'));
console.log(doopizlist.pluck('firstName')); // logs 2 duplicate arrays
});
return results;
},
error: function(doopizlist, error) {
console.log("error"); // The collection could not be retrieved.
}
});
console.log(testt); // logs "a b.promise...." message instead of firstNames

Answer 1

The duplication issue is because you are looping over doopizlist twice, once with each and again with pluck. Pluck is just basically shorthand of the map method.
The second issue is, you are expecting testt is the resulting value, when actually it is an instance of jqXHR, which is something known as a promise. So you can use the then method to log the value of the result.
var DoopizCollection = Parse.Collection.extend({
model: Subscribers
}
);
var doopizlist = new DoopizCollection();
var testt;
testt = doopizlist.fetch({
success: function(results) {
return results.pluck('firstName');
},
error: function(results, error) {
console.log("error"); // The collection could not be retrieved.
}
});
testt.then(function(results) {
console.log(results);
});