an example for node-promise (https://github.com/holyzfy/node-promise)

example-promise.js

var promise = require("./promise");

promise.execute(function(callback){
    asyncOperation(callback);
}).then(function(result){
    console.log("on succ: ", result);
}, function(err) {
    console.log("on fail: ", err);
});


function asyncOperation(callback) {
    setTimeout(function(){
        callback(null, "succ result");
        //callback(new Error("an err"));
    }, 2000);
};