flow-control.js

var co = require('co');

function getRandomArbitrary(min, max) {
  return Math.floor(Math.random() * (max - min) + min);
}

co(function *(){
  // yield any promise 
  //setTimeout(function(){
  	var result = yield Promise.resolve(true);
  //}, getRandomArbitrary(1000,2000))
}).catch(onerror);
 
co(function *(){
  // resolve multiple promises in parallel 
  var a = Promise.resolve(1);
  var b = Promise.resolve(2);
  var c = Promise.resolve(3);
  var res = yield [a, b, c];
  console.log('Result: ' + res);
  // => [1, 2, 3] 
}).catch(onerror);
 
// errors can be try/catched 
co(function *(){
  try {
    yield Promise.reject(new Error('boom'));
  } catch (err) {
    console.error('Error: ' + err.message); // "boom" 
 }
}).catch(onerror);
 
function onerror(err) {
  // log any uncaught errors 
  // co will not throw any errors you do not handle!!! 
  // HANDLE ALL YOUR ERRORS!!! 
  console.error('Error: ' + err.stack);
}