code: function waitFor(checkFn, timeout, cb) {
    var start = Date.now();
    function runWaitFor() {
      if (checkFn()) {
        cb();
      } else if ((Date.now() - start) <= timeout) {
        setTimeout(runWaitFor, 100);
      } else {
        cb(new Error('Timeout of ' + timeout + 'ms reached. This usually means something went wrong. Please try your SVGs inside icomoon itself, https://icomoon.io/app-old'));
      }
    }
    runWaitFor();
  }
docs: Run a check function every 100 ms