Using Q.js, a while loop where the condition is itself a promise

promiseWhilePromise.js

'use strict';

var Q = require('q');

// `condition` is a function that returns a boolean
// `body` is a function that returns a promise
// returns a promise for the completion of the loop
function promiseWhile(condition, body) {
  var done = Q.defer();

  function loop() {
    // When the result of calling `condition` is no longer true, we are
    // done.
    if (!condition()) return done.resolve();
    // Use `when`, in case `body` does not return a promise.
    // When it completes loop again otherwise, if it fails, reject the
    // done promise
    Q.when(body(), loop, done.reject);
  }

  // Start running the loop in the next tick so that this function is
  // completely async. It would be unexpected if `body` was called
  // synchronously the first time.
  Q.nextTick(loop);

  // The promise
  return done.promise;
}

// Similar to above but the condition is now a promise
function promiseWhilePromise(condition, body) {
  var deferred = Q.defer();

  function loop() {
    // When the result of calling `condition` is no longer true, we are
    // done.
    condition().then(function(bool) {
      if (!bool) {
        return deferred.resolve();
      } else {
        // Use `when`, in case `body` does not return a promise.
        // When it completes loop again otherwise, if it fails, reject the
        // done promise
        return Q.when(body(), loop, deferred.reject);
      }
    });
  }

  // Start running the loop in the next tick so that this function is
  // completely async. It would be unexpected if `body` was called
  // synchronously the first time.
  Q.nextTick(loop);

  // The promise
  return deferred.promise;
}
// Usage
var index = 1;


function conditionP() {
  var deferred = Q.defer();
  Q.delay(500).then(function() {
    deferred.resolve(index <= 5);
  });
  // reject?
  return deferred.promise;
}

function work() {
  console.log(index);
  index++;
  return Q.delay(500); // arbitrary async
}

promiseWhilePromise(conditionP, work).then(function () {
  console.log("done");
}).done();

While running those loop, we do have some SIGABRT which cause server to restart. I didn't found a way to fix the problem. I suspect problems comes from Q library itself.