Sorting strings in reverse order with backbone.js

Question

I\'m trying to sort a Backbone.js collection in reverse order. There are previous replies on how to do this with integers, but none with strings.

var Chapter         


        

Answer 1

There are two versions of the comparator function that you can use, either the sortBy version - which was shown in the example, which takes one parameter, or sort - which you can return a more standard sort function, which the documentation says:

"sortBy" comparator functions take a model and return a numeric or string value by which the model should be ordered relative to others. "sort" comparator functions take two models, and return -1 if the first model should come before the second, 0 if they are of the same rank and 1 if the first model should come after.

So in this case, we can write a different comparator function:

var Chapter  = Backbone.Model;
var chapters = new Backbone.Collection;

chapters.comparator = function(chapterA, chapterB) {
  if (chapterA.get('title') > chapterB.get('title')) return -1; // before
  if (chapterB.get('title') > chapterA.get('title')) return 1; // after
  return 0; // equal
};

chapters.add(new Chapter({page: 9, title: "The End"}));
chapters.add(new Chapter({page: 5, title: "The Middle"}));
chapters.add(new Chapter({page: 1, title: "The Beginning"}));

alert(chapters.pluck('title'));

So you should get as a response:

"The Middle", "The End", "The Beginning"