Google Apps Script for adding a Sheets function for estimating the austrian income tax

atincometax.js

function atincometax(income) {
  var url = "http://chh-at-tax.herokuapp.com/income-tax";
  
  income = parseInt(income, 10);
  
  var response = UrlFetchApp.fetch(url, {
    method: "post",
    payload: JSON.stringify({income: income})
  });
  
  var data = JSON.parse(response.getContentText());
  
  return data.tax;
}