Cached custom function for G Suite / Google Sheets in Apps Script

Cached-leftpad-custom-function.gs

kch = CacheService.getDocumentCache(); // set up the cache service as a global object


function lp(num){
  return ("0000" + num).slice(-2) // elegant
  Utilities.sleep(500);
}

/**
 * A function to left pad an integert with 0 if less than two digits
 *
 * @param {Num} number - number to pad
 * @return {Padded} string - the number,zero padded to 2 spaces
 * @customfunction
 */
function leftpad(num){
  var r = kch.get(num);
  if (r) {
    Utilities.sleep(500);
    return r
  } else {
    r = lp(num);
    kch.put(num,r,1200);
    Utilities.sleep(500);
    return r
  }
}



function testpad(){
  var num_a = 5;
  var num_b = 10;
  var pad_a = leftpad(num_a);
  var pad_b = leftpad(num_b);
}