Sequential timeouts by promises

timeout-seq.js

// node --harmony timeout-seq.js

[3,5,10]
.map(function(sec) { return sec * 1000; })
.map(function(duration) {
  return function task(resolve) {
    setTimeout(function() {
      console.log(duration);
      resolve();
    }, duration);
  };
})
.reduce(function(prev, task) {
  return prev.then(function() { return new Promise(task); });
}, Promise.resolve())
.then(function() {
  console.log('done');
});