download string as text file

downloadString.js

function downloadString(text, fileType, fileName) {
  var blob = new Blob([text], { type: fileType });

  var a = document.createElement('a');
  a.download = fileName;
  a.href = URL.createObjectURL(blob);
  a.dataset.downloadurl = [fileType, a.download, a.href].join(':');
  a.style.display = "none";
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  setTimeout(function() { URL.revokeObjectURL(a.href); }, 1500);
}

// downloadString("a,b,c\n1,2,3", "text/csv", "myCSV.csv")

I'm actually not sure what the timeout is for. I wrote this so long ago that I don't remember.

Looks like there's a more robust and actively maintained solution here: https://github.com/eligrey/FileSaver.js/blob/master/src/FileSaver.js

It also uses a timeout before revoking the url, set to 40 seconds.

Also, from that repo's README:

If you need to save really large files bigger than the blob's size limitation or don't have enough RAM, then have a look at the more advanced StreamSaver.js that can save data directly to the hard drive asynchronously with the power of the new streams API. That will have support for progress, cancelation and knowing when it's done writing

Wow ty, I will have a look at it

Fantastic