Download files with AJAX (axios)

download-file.js

axios({
  url: 'http://localhost:5000/static/example.pdf',
  method: 'GET',
  responseType: 'blob', // important
}).then((response) => {
  const url = window.URL.createObjectURL(new Blob([response.data]));
  const link = document.createElement('a');
  link.href = url;
  link.setAttribute('download', 'file.pdf');
  document.body.appendChild(link);
  link.click();
});

Using responseType: 'blob' Axios returns a blob, you don't need to convert it into a blob again.

axios({
  url: 'http://localhost:5000/static/example.pdf',
  method: 'GET',
  responseType: 'blob', // important
}).then((response) => {
  const url = window.URL.createObjectURL(response.data));
  const link = document.createElement('a');
  link.href = url;
  link.setAttribute('download', 'file.pdf');
  document.body.appendChild(link);
  link.click();
});

And using FileSaver you can save some lines of code increasing the browsers compatibility:

import { saveAs } from 'file-saver'

axios({
  url: 'http://localhost:5000/static/example.pdf',
  method: 'GET',
  responseType: 'blob', // important
}).then((response) => {
  saveAs(response.data, 'file.pdf');
});

Asking axios to return a blob instead of returning text and building a blob saved me days of banging my head on the desk.
Was constantly seeing corrupted data and couldn't figure out why. The file-saver package made my code a ton cleaner as well.

Thank you so, so much @sergiop!!!