fibonacci_checker.js

function fibonacciChecker(num) {
  var series = [1, 1];
  while (series[series.length - 1] < num) {
    var item = series[series.length - 2] + series[series.length - 1];
    series.push(item);
  }
  if (series[series.length - 1] === num) {
    return true;
  } else {
    return false
  }
}