Backbone.js collection comparator sort by multiple fields?

Question

  this.col = Backbone.Collection.extend({
    model: M,
    comparator: function(item) {
      return item.get(\"level\");
    }
  });

This above c

Answer 1

The main thing is that Backbone sorts by a single relative value of one item to another. So it's not directly possible to sort twice in a single collection but I'd try this.

this.col = Backbone.Collection.extend({
    model: M,
    comparator: function(item) {
      // make sure this returns a string!
      return item.get("level") + item.get("title");
    }
});

What this will do is return a string of like "1Cool", "1title", "2newTitle" ... Javascript should sort the strings by the numerical character first then each character afterwards. But this will only work as long as your levels have the same amount of digits. IE "001title" vs "200title". The main idea though is that you need to produce two comparable objects, line a number or string, that can be compared to each other based on one criteria.

Other solution would be to use underscore to "groupby" your level then use "sortby" to manually sort each level group then manually replace the underlying collection with this newly created array. You can probably setup a function to do this whenever the collection "changes".