Parse string into array of maps using callback

parseString.js

/**
 * @author Juan Orozco
 */

var can = require('can');
require('can/map/define/define');

// The default map for the character item
// The type can be anything, it should be used to mark what the item is
// The value is the character
var DefaultMap = can.Map.extend({
    define: {
        type: {
            value: '',
            type: 'string'
        },
        value: {
            value: '',
            type: 'string'
        }
    }
});

var ParseOpts = can.Map.extend({
    define: {
        raw: {
            value: '',
            type: 'string'
        },
        callback: {
          value: can.noop
        },
        ItemMap: {
          Value: DefaultMap
        }
    }
});

var Parsed = can.List.extend({});

var ParseString = can.Construct.extend({
    parsed: null,
    opts: new ParseOpts({}),
    init: function (strToParse, opts) {
        this.opts = new ParseOpts({
            raw: strToParse,
            callback: opts.callback || can.noop,
            ItemMap: opts.Map || DefaultMap
        });
        Parsed.Map = opts.Map || DefaultMap;
        this.parsed = new Parsed([]);

    },
    parse: function () {
        var opts = this.opts;
        var strToParse = opts.attr('raw');
        var Map = opts.attr('ItemMap');
        // Set up empty map
        var previous = new Map({});

        // Loop through item and process it
        for (var i = 0; i < strToParse.length; i++) {
            // Set up initial map for parser
            var current = new Map({value: strToParse[i]});

            // Call the passed in callback for parsing
            // The previous object is passed as sugar but the context
            // will always be the main object which has the parsed array
            var resp = this.opts.callback.call(this.parsed, previous, current, i, strToParse);

            // Don't keep the current item if parser returns false
            if (resp !== false) {
                this.parsed.push(current);
            }
            previous = current;
        }
        return this.parsed;
    }
});

module.exports = ParseString;