next-update/test/time-limit-promise.js

// how to time limit a promise?

var Q = require('q');
var started = +(new Date());

console.stamp = function stamp() {
  var elapsed = +(new Date()) - started;
  var messageArgs = ['at %d ms:', elapsed].concat(Array.prototype.slice.call(arguments, 0));
  console.log.apply(console, messageArgs);
}

function onOk(value) {
  console.stamp('promise resolved ok', value);
}

function onError(value) {
  console.stamp('promise error with value', value);
}

// "normal" promise-returning function, knows nothing about the time limit
function longAction() {
  var deferred = Q.defer();

  console.stamp('started long-running promise');
  setTimeout(function () {
    console.stamp('resolving long-running promise with 42 after 1 second');
    return deferred.resolve(42);
  }, 1000);

  return deferred.promise;
}

longAction()
  .timeout(400, 'timed out')
  .then(onOk, onError)
  .done();