Backbone.Model with auto-properties

Backbone.AutoModel.js

'use strict';

var Backbone = require('backbone');

var ModelAbstract = Backbone.Model.extend({

    /**
     * Create calculatable properties.
     * @example
     * __autos__: {
     *     'fieldName': ['torrent dont_seed', function () {}]
     *     'fieldName': ['torrent dont_seed', 'methodName'], // will be used this.methodName
     *     'fieldName': ['torrent dont_seed'], // will be used this.fieldName
     * }
     * function should return value which will be set to `fieldName` model field.
     *
     * @param {Object} [autos=this.__autos__]
     * @protected
     */
    _processAutos: function (autos) {
        if (!autos) {
            autos = _.result(this, '__autos__')
        }

        if (!autos) {
            return;
        }

        Object.keys(autos).forEach(function (autoName) {
            var handler = autos[autoName];
            var keys = handler[0];
            var callback;

            if (handler.length === 2) {
                callback = typeof handler[1] === 'string' ? this[handler[1]] : handler[1];
            } else {
                callback = this[autoName];
            }

            this._genAutoProp(keys, autoName, callback);
        }, this);
    },

    /**
     *
     * @param {String} keys space-delimited field names
     * @param {String} autoName
     * @param {Function} callback
     * @protected
     */
    _genAutoProp: function (keys, autoName, callback) {
        var eventName = 'change:' + keys.replace(/ /g, ' change:');
        var handler = function () {
            this.set(autoName, callback.call(this))
        }.bind(this);

        this.on(eventName, function () {
            setTimeout(handler, 0)
        });

        handler(); // fire right at the start
    },

    initialize: function (attributes, options) {
        this._processAutos();

        ModelAbstract.__super__.initialize.apply(this, arguments);
    }
});

module.exports = ModelAbstract;