poll.js

/**
 * Executes a function with a given interval
 * @arg {function} fn - Function to execute, 
 * @arg {integer} interval - Interval in milliseconds
 */
function poll(fn, interval) {
  fn(() => setTimeout(() => poll(fn, interval), interval));
}

poll(retry => $.get('/status').success(res => res.status === 'pending' && retry()));