Download a CSV file gotten using fetch (necessary when headers needed, eg. with token authorization)

download.js

fetch(request).then(
  response => {
    if (response.status >= 200 && response.status < 300) {
      if (response.headers.get('Content-Type') === 'text/csv') {
        response.text().then(
          text => {
            const windowUrl = window.URL || window.webkitURL;
            const blob = new Blob([text], {type: 'text/csv'});
            const url = windowUrl.createObjectURL(blob);
            window.location = url;
          }
        );
      }
    }
  },
  response => {}
);