a simple implementation of a "all" callback pattern such that all the callback functions in the `entries` array complete successfully before progressing

callbackAll.js

var all = function (entries, cb) {
  var finishers = entries.length;
	
  var allCB = (function(cb) {
    return function (res) {
      if (res) {
        if (--finishers === 0) cb(res);
      } else {
        cb(false);
      }
    }
  })(cb);
	
  entries.map(entry => { entry(data, allCB); });
}