recordHistory_gcal_cryptofinance.js

function recordHistory() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  
  // Toggle a cell that is used in one of a CRYPTOFINANCE formula to force-trigger a refresh
  var r = ss.getSheetByName("folio").getRange("A30");
  var unit = r.getValues()[0][0];
  r.setValue(unit==='BTCEUR'?'BTC/EUR':'BTCEUR');
  
  // accumulate history
  var sheet = ss.getSheetByName("History");
  var values;
  for (var i=0; i<20; i++) { // try each second for 20 seconds
    Utilities.sleep(1000);
    var source = sheet.getRange("A2:G2");
    values = source.getValues();
    if (!isNaN(values[0][1])) { // if values is a number, we are done, otherwise it means we need to try again
      break;
    }
  }
  if (isNaN(values[0][1])) { // this was not successful and we must not append a row
    return;
  }
  // append row to history
  values[0][0] = new Date();
  sheet.appendRow(values[0]);
}