A rewrite of redux

redux.light.js

var _ = require('lodash'); 
var globalStore;

function getInstance(){ 
 if (!globalStore) globalStore = createStore();
 return globalStore;
}

function createStore() { 
 var currentState = {}; 
 var subscribers = []; 
 var currentReducerSet = {}; 
 currentReducer = function(state, action) { 
  return state; 
 };
 
 function dispatch(action) {
  var prevState = currentState;
  currentState = currentReducer(_.cloneDeep(currentState), action);
  subscribers.forEach(function(subscriber){
   subscriber(currentState, prevState);
  });
 }
 
 function addReducers(reducers) {
  currentReducerSet = _.assign(currentReducerSet, reducers);
  currentReducer = function(state, action) {
   var ret = {};
   _.each(currentReducerSet, function(reducer, key) {
    ret[key] = reducer(state[key], action);
   });
   return ret;
  };
 }
	
 function subscribe(fn) {
  subscribers.push(fn);
 }
	
 function unsubscribe(fn) {
  subscribers.splice(subscribers.indexOf(fn), 1);
 }
	
 function getState() {
  return _.cloneDeep(currentState);
 }
	
 return {
  addReducers,
  dispatch,
  subscribe,
  unsubscribe,
  getState
 };
}
module.exports = getInstance();