AliasDS = Ext.extend(Ext.data.JsonStore, {
    constructor: function(cfg) {
        cfg = cfg || {};
        AliasDS.superclass.constructor.call(this, Ext.apply({
            storeId: 'AliasDS',
            root: 'data',
            url: 'data/alias.json',
            fields: [
                {
                    name: 'alias'
                },
                {
                    name: 'idCanal'
                },
                {
                    name: 'idCartaServicio'
                }
            ]
        }, cfg));
    }
});
new AliasDS();