ふつうにいくよなぁ...

callback.js

var params = {
  num : 3,
  callback : function(response){
    console.log(response);
  }
}

var runner = function(prms){
  setTimeout(function(){
    var res = prms.num * 100;
    prms.callback(res);
  },100);
}

runner(params);// 300