gistfile1.txt

[p1, p2, p3, p4].reduce(function(result, current){ 
  return result.then(function(context) {
    return context.done?    context
    :      /* otherwise */  b.then(function(value) {
                              return shouldWeGoOn(value)?  { done: false, values: context.concat([value]) }
                              :      /* otherwise */       { done: true, values: context }
                            })
  })
}, Promise.of({ done: false, values: [] })