GASで銀行くんAPIを実行して銀行コードと支店コードを全件取得

function ginko() {  
  const baseUrl = `https://bank.teraren.com/banks.json?per=2000`;

  const response = UrlFetchApp.fetch(baseUrl);
  const json = JSON.parse(response.getContentText());

  const pasteArr = json.map(x => [x.code, x.normalize.name]);
  const sh = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("銀行くん");
  sh.getRange("A2:B").clear();
  sh.getRange(2, 1, pasteArr.length, pasteArr[0].length).setValues(pasteArr);
}


function shiten(){
  const ss = SpreadsheetApp.getActiveSpreadsheet();
  const bankSh = ss.getSheetByName("銀行くん");
  const bankJson = bankSh.getRange("A2:B").getValues().filter(x => x[0])
                    .map(x => ({code:x[0], name:x[1]}));

  bankJson.forEach(x => {
    const url = `https://bank.teraren.com/banks/${x.code}/branches.json?per=1000`;
    const response = UrlFetchApp.fetch(url);
    const responseJson = JSON.parse(response.getContentText());
    x.brunchJson = responseJson;
  });

  const maxColumns = Math.max(...bankJson.map(x => x.brunchJson.length + 2));
  const pasteArr = bankJson.map(x => {
    const rowData = [x.code, x.name];
    x.brunchJson.forEach(y => rowData.push(`${y.code}_${y.name}`));
    while (rowData.length < maxColumns) {
      rowData.push("");
    }
    return rowData;
  });

  const brunchSh = ss.getSheetByName("銀行くん支店");
  brunchSh.getRange("2:1500").clear();
  brunchSh.getRange(2, 1, pasteArr.length, maxColumns).setValues(pasteArr);
}