Emberjs & Ember-data lazy load one to many (1-n) relationships

ember data lazyLoadedHasMany.js

DS.lazyLoadedHasMany = function(type, options) {
    options = options || {};

    return Ember.computed(function(key, value) {

        var parts = this.constructor.toString().split('.'),
            name = parts[parts.length - 1];

        name = name[0].toLowerCase() + name.slice(1);

        var foreignKey = name + "Id",
            foreignField = name;

        options.foreignKey = options.foreignKey || foreignKey;
        options.foreignField = options.foreignField ||foreignField;

        var lazyLoadedHasMany = this.get('data.lazyLoadedHasMany');
        if (undefined === lazyLoadedHasMany) {
            lazyLoadedHasMany = {};
            this.set('data.lazyLoadedHasMany', lazyLoadedHasMany);
        }

        if (typeof type === 'string') {
            type = Ember.get(type);
        }

        var _this = this,
            data = lazyLoadedHasMany[key];

        if (undefined === data) {

            data = Ember.ArrayProxy.create({
                isLoading: true,
                content: []
            });

            this.set('data.lazyLoadedHasMany.'+key, data);

            var findOptions = {};
            findOptions[options.foreignKey] = _this.get('id');

            type.find(findOptions).then(function() {
                data.set('isLoading', false);
                data.set('content', type.all().filter(function(element) {
                    return element.get(options.foreignField) === _this;
                }));
            });
        }

        return data;
    }).property();
};