关于DDD的Repository仓库需要哪些方法？

function Repo(){}

var r = Repo.prototype;

r.create = function(cb){

};

r.find = function(){
	
};

r.findById = function(id,cb){
	
};

r.removeById = function(){

};

<p class="indent">

var repo = {
  find:function(){}
 ,findById:function(){}
 ,removeById:function(){}
 ,create:function(){}
}

<p class="indent">