Functional attributes in Backbone

Backbone.Model.js

var Model = Backbone.Model.extend({

    get: function (attribute) {
        var value = Backbone.Model.prototype.get.call(this, attribute);

        if(_.isFunction(value)) {
            value = value.call(this);
        }

        return value;
    },

    toJSON: function () {
        var obj = Backbone.Model.prototype.toJSON.apply (this, arguments);

        _.mapObject(obj, function (value, key) {
            if(_.isFunction(value)) {
                obj[key] = value();
            }
        });

        return obj;
    }
});

Backbone.sync.js

Backbone.sync = function (method, model, options) {
    var self = this;

    options = options || {};

    // Execute function-properties
    options.attrs && _.mapObject(options.attrs, function (value, key) {
        if(_.isFunction(value)) {
            options.attrs[key] = value.call(self);
        }
    });

    return BackboneSync.call(this, method, model, options);
};