Reset “insertion sort order” for backbone collection

0
votes

I am setting and unsetting comparator functions on my backbone collections at runtime, and I would like to know if there is a way to "reset" the collection to its original insertion order. For example...

var Mod = Backbone.Model.extend({});
var Col = Backbone.Collection.extend({ model: Mod });
var col = new Col([
    { name: "andy" },
    { name: "chad" },
    { name: "ashley" },
    { name: "louis" }
]);

col.comparator = function(p1, p2) {
    return p1.get('name') < p2.get('name') ? -1
        : (p1.get('name') > p2.get('name') ? 1 : 0 );
}
col.sort();

col.comparator = false;

// throws, was hoping this would return 
// the collection to insertion order
col.sort();

Please disregard the fact that the comparator function I am setting here could be replaced with the sortBy implementation. This is just a contrived example. It is clear to me from the Backbone source that if you try and sort a collection with no comparator, it will throw:

// ... from BB source ...
sort: function(options) {
    if (!this.comparator) throw new Error('Cannot sort a set without a comparator');
    // ...

Is there any way to return the order of the collection to insertion order?

2
javascriptbackbone.js
Is the original order arbitrary? If so, it will be hard to get it back without re-fetching or manually resetting the collection. If the original order was sorted by id, or some other value, you would be able to use a different comparator function. Is the data coming from a server? I doubt the server is returning arbitrary order, so maybe it is sorted by id or auto-increment value or date, and you can try to sort by the same thing here. - Paul Hoenecke
the order I want is just the insertion order. I believe @Loamhoof is correct in that I'll need to just keep track of this order throughout the life of the collection - AndyPerlitch
Hmm, before sorting you could add a new attribute to each model model.set({originalOrder: num++}) then sort later based on this... But yes, @Loamhoof is right if the collection is in an arbitrary order. - Paul Hoenecke

2 Answers

0
votes

No, there's none. Though you could easily keep some array that'd keep this information to use it later. Redefine the add method, 'hack' the parse one...
But yeah, sadly, it'd make no sense to have one.

0
votes

You could save the original in the Collection. Something like:

col.originalComp = col.comparator;
col.comparator = function(){};
...Do Stuff ...
col.comparator = col.originalComp; //Back to original