Promise "loop" using the Bluebird library Updated to p1nox's comment from the original

promise_while_loop.js

/*
p1nox commented 19 days ago
I was digging a bit about this and I found some interesting links:

petkaantonov/bluebird#553 (comment)
http://stackoverflow.com/a/29396005
http://stackoverflow.com/a/24660323

Simplifications:
*/

function promiseWhile(predicate, action) {
    function loop() {
        if (!predicate()) return;
        return Promise.resolve(action()).then(loop);
    }
    return Promise.resolve().then(loop);
}

//  Or...

var promiseWhile = Promise.method(function(condition, action) {
    if (!condition()) return;
    return action().then(promiseWhile.bind(null, condition, action));
});

/// PAEz - here it is with a delay function
  function promiseWhile(predicate, action, delay) {
    function wait() {
      if (delay) return new Promise(function(resolve, reject) {
          window.setTimeout(resolve, delay);
        });
      else return;
    }
    function loop() {
      if (!predicate()) return;
      return Promise.resolve(action()).then(wait).then(loop);
    }
    return Promise.resolve().then(loop);
  }
  
  // test
  var counter = 0;

  function action() {
    return new Promise(function(resolve, reject) {
      console.log(counter);
      resolve();
    })
  }

  function cond() {
    if (counter++ < 10) return true;
    return false;
  }

  promiseWhile(cond, action, 500)
    .then(function() {
      console.log('done')
    })