Canjs - Extending can.Model with additional Methods

I'm not the first person to ask this... the answers basically say "Well you're doing REST wrong." Fair enough, but development is filled with tradeoffs and I often find myself not in a position to rewrite the API.

Moving on to the problem at hand, what's the most elegant way to add a method for some resource to a model?

var Issue = can.Model.extend({
  findAll: 'GET Issues',
  findOne: 'GET Issues/{id}',
  findRelated: can.Model.makeFindAll(function(params) {
    return can.ajax({
      type: 'GET',
      url: 'Issues/'+params.id+'/'
    });
  })
},{});

jsfiddle

If I understand the question correctly, you want to get an Issue.List from findRelated.

var Issue = can.Model.extend({
  findAll: 'GET Issues',
  findOne: 'GET Issues/{id}',

  findRelated: function(params) {
    var deferred = new can.Deferred();

    can.ajax({
      type: 'GET',
      url: 'Issue/'+params.id+'/Related'
    }).then(function(response) {
      // success
      deferred.resolve(Issue.models(response || []));
    }, function(xhr, textStatus, err) {
      // failure
      deferred.reject(err);
    });

    return deferred;
  }

},{});

jsfiddle