gistfile1.js

// using Deferreds

function delay(value, timeout) {
  var deferred = Q.defer()
  
  if (typeof timeout !== 'number') {
    deferred.reject(new TypeError('timeout must be a number'))
  } else {
     setTimeout(function () {
      deferred.resolve(value)
    }, timeout) 
  }
  
  return deferred.promise
}

// using Promise constructor resolver
function delay2(value, timeout) {
  return Q.promise(function (resolve, reject) {
    if (typeof timeout !== 'number') {
      reject(new TypeError('timeout must be a number'))
    } else {
      setTimeout(function () {
        resolve(value)
      }, timeout)
    }
  })
}

// using resolver syntax gives you the same control over resolving and rejecting promises
// without having to introduce a new concept when explaining it for the first time