The Flux store creator that I'm currently using (with Facebook's own flux repo, which includes just a dispatcher). `chirps.js` is an example of it in action.

chirps.js

var constants = require('../constants');

var ChirpStore = module.exports = require('./store').extend({
  init: function () {
    this.bind(constants.RECEIVE_CHIRPS, this.loadChirps);
    this.bind(constants.CREATED_CHIRP, this.loadChirps);
  },
  loadChirps: function (data) {
    data = ({}).toString.call(data).indexOf('Array') > 0 ? data : [data];
    data.forEach(ChirpStore.add.bind(ChirpStore));
  }
});

store.js

var assign = require('object-assign');
var CHANGE_EVENT = 'CHANGE';

exports.extend = function (methods) {
  var store = assign({}, require('events').EventEmitter.prototype, {
    _id: 0,
    _data: {},
    add: function (obj) {
      if (!obj.id) {
        var id = this._id++;
        obj.id = id;
      } else {
        if (obj.id > this._id) this._id = obj.id;
      }
      this._data[obj.id] = obj;
      return obj;
    },
    all: function () {
      return Object.keys(this._data).map(function (id) { return this._data[id]; }.bind(this));
    },
    emitChange: function () {
      this.emit(CHANGE_EVENT);
    },
    addChangeListener: function(callback) {
      this.on(CHANGE_EVENT, callback);
    },
    removeChangeListener: function(callback) {
      this.removeListener(CHANGE_EVENT, callback);
    },
    actions: {},
    bind: function (actionType, action) {
      this.actions[actionType] = action.bind(this);
    }
  }, methods);

  store.init();

  require('../dispatcher').register(function (action) {
    store.actions[action.actionType](action.data);
    store.emitChange();
  });

  return store;
};