Google script custom functions for KRW

code.gs

function pad0(num) {
  return num < 10 ? '0' + num.toString() : num.toString();
}

function getDateStringDaysAgo(days) {
  const date = new Date(Date.now() - (days * 24 * 60 * 60 * 1000));
  return date.getFullYear() + "-" + pad0(date.getMonth() + 1) + "-" + pad0(date.getDate());
}

/**
 * Returns current value of given gold as Korean Won (KRW). 
 * @param [gram=1] {number} Gold in gram.
 * @return {number} Current value in KRW.
 * @customFunction
 */
function getCurrentGoldValueInKRW(gram) { 
  const GramPerOunce = 0.035274;
  var response = UrlFetchApp.fetch("https://www.quandl.com/api/v3/datasets/WGC/GOLD_DAILY_KRW.json?start_date=" + getDateStringDaysAgo(20));
  const body = JSON.parse(response.getContentText());
  const krwPerOunce = body.dataset.data[0][1];
  const ret = GramPerOunce * krwPerOunce * (gram || 1);
  return ret;
}

/**
 * Returns easy to read string of KRW. round off below 10,000 KRW.
 * @param krw {number} Korean won to convert into string.
 * @return {string}
 * @customFunction
 */
function toEasyKRWCurrencyString(krw) {
  const bil = Math.floor(krw / 100000000);
  const man = Math.floor((krw % 100000000) / 10000);
  
  const msg = [];
  bil && msg.push(bil + '억');
  man && msg.push(man + '만');
  msg.length ? msg.push('원') : msg.push(krw + '원');
 
  return msg.join(' ');
}