Download response.data as a file, through Blob()

downloadFile.js

// 'downloadFile.js', written by blending two solutions:
// 'js-download' https://github.com/kennethjiang/js-file-download
// 'Anders Paulsen' https://blog.jayway.com/2017/07/13/open-pdf-downloaded-api-javascript/

export function downloadFile(data, filename, mime) {
  // It is necessary to create a new blob object with mime-type explicitly set
  // otherwise only Chrome works like it should
  const blob = new Blob([data], {type: mime || 'application/octet-stream'});
  if (typeof window.navigator.msSaveBlob !== 'undefined') {
    // IE doesn't allow using a blob object directly as link href.
    // Workaround for "HTML7007: One or more blob URLs were
    // revoked by closing the blob for which they were created.
    // These URLs will no longer resolve as the data backing
    // the URL has been freed."
    window.navigator.msSaveBlob(blob, filename);
    return;
  }
  // Other browsers
  // Create a link pointing to the ObjectURL containing the blob
  const blobURL = window.URL.createObjectURL(blob);
  const tempLink = document.createElement('a');
  tempLink.style.display = 'none';
  tempLink.href = blobURL;
  tempLink.setAttribute('download', filename);
  // Safari thinks _blank anchor are pop ups. We only want to set _blank
  // target if the browser does not support the HTML5 download attribute.
  // This allows you to download files in desktop safari if pop up blocking
  // is enabled.
  if (typeof tempLink.download === 'undefined') {
    tempLink.setAttribute('target', '_blank');
  }
  document.body.appendChild(tempLink);
  tempLink.click();
  document.body.removeChild(tempLink);
  setTimeout(() => {
    // For Firefox it is necessary to delay revoking the ObjectURL
    window.URL.revokeObjectURL(blobURL);
  }, 100);
}

// To use:
// import {downloadFile} from '../helpers/downloadFile'; // <= HERE
// export function fetchReport(token, sessionId) {
//   return dispatch => {
//     dispatch({type: 'FETCH_REPORT'});
//     axios.get(`${API_ROOT}/report/${sessionId}`, {
//       headers: {
//         Authorization: `Custom ${token}`
//       }
//     })
//       .then(response => {
//         dispatch({type: 'FETCH_REPORT_FULFILLED', payload: response.data});
//         downloadFile(response.data, 'ActionReport.csv', 'text/csv'); // <= HERE
//       })
//       .catch(err => {
//         dispatch({type: 'FETCH_REPORT_REJECTED', payload: err});
//       });
//   };
// }
// Then:
// dispatch(fetchReport(userToken, SessionId)); // at component level

// ---------------- sources ---------------- //

// // https://github.com/kennethjiang/js-file-download
// module.exports = function(data, filename, mime) {
//   var blob = new Blob([data], {type: mime || 'application/octet-stream'});
//   if (typeof window.navigator.msSaveBlob !== 'undefined') {
//       // IE workaround for "HTML7007: One or more blob URLs were
//       // revoked by closing the blob for which they were created.
//       // These URLs will no longer resolve as the data backing
//       // the URL has been freed."
//       window.navigator.msSaveBlob(blob, filename);
//   }
//   else {
//       var blobURL = window.URL.createObjectURL(blob);
//       var tempLink = document.createElement('a');
//       tempLink.style.display = 'none';
//       tempLink.href = blobURL;
//       tempLink.setAttribute('download', filename);

//       // Safari thinks _blank anchor are pop ups. We only want to set _blank
//       // target if the browser does not support the HTML5 download attribute.
//       // This allows you to download files in desktop safari if pop up blocking
//       // is enabled.
//       if (typeof tempLink.download === 'undefined') {
//           tempLink.setAttribute('target', '_blank');
//       }

//       document.body.appendChild(tempLink);
//       tempLink.click();
//       document.body.removeChild(tempLink);
//       window.URL.revokeObjectURL(blobURL);
//   }
// }

// // https://blog.jayway.com/2017/07/13/open-pdf-downloaded-api-javascript/
// function showFile(blob) {
//   // It is necessary to create a new blob object with mime-type explicitly set
//   // otherwise only Chrome works like it should
//   var newBlob = new Blob([blob], {type: "application/pdf"})
//   // IE doesn't allow using a blob object directly as link href
//   // instead it is necessary to use msSaveOrOpenBlob
//   if (window.navigator && window.navigator.msSaveOrOpenBlob) {
//     window.navigator.msSaveOrOpenBlob(newBlob);
//     return;
//   }
//   // For other browsers:
//   // Create a link pointing to the ObjectURL containing the blob.
//   const data = window.URL.createObjectURL(newBlob);
//   var link = document.createElement('a');
//   link.href = data;
//   link.download="file.pdf";
//   link.click();
//   setTimeout(() => {
//     // For Firefox it is necessary to delay revoking the ObjectURL
//     window.URL.revokeObjectURL(data);
//   }, 100);
// };
// fetch([url to fetch], {[options setting custom http-headers]})
// .then(r => r.blob())
// .then(showFile)