promiseWhile

promise-utils.js

// Based on http://blog.victorquinn.com/javascript-promise-while-loop and https://github.com/stevenzeiler/promise-while



function promiseWhile(condition, action) {
  return new Promise((resolve, reject) => {
    const loop = () => 
      Promise.resolve(condition())
        .then(keepGoing => {
          if (!keepGoing) { return resolve(); }

          Promise
            .resolve(action())
            .then(loop);
        })
        .catch(err => reject(err));   

    loop();
  });
}

var promiseNot = condition => Promise.resolve(condition).then(result => !result);

var promiseUntil = (condition, action) => promiseWhile(() => promiseNot(condition()), action);