Promise.while

promise_while.js

var Promise = require("bluebird");

Promise.while = function(condition, action) {
  var resolver = Promise.defer();
  var loop = function() {
    if (!condition()) return resolver.resolve();
    return Promise.cast(action())
      .then(loop)
      .catch(resolver.reject);
  };
    process.nextTick(loop);
    return resolver.promise;
};

var i = 0;

Promise.while(function() {
  return i < 10;
}, function() {
  return new Promise(function(resolve, reject) {
    i++;
    if (i == 10) response = 'it is done!';
    resolve(response);
  })
})
.then(function(response) {
  assert(response == 'it is done!');
})