JavaScript: Save a blob to disc

gistfile1.js

var saveBlob = (function () {
    var a = document.createElement("a");
    document.body.appendChild(a);
    a.style = "display: none";
    return function (blob, fileName) {
        var url = window.URL.createObjectURL(blob);
        a.href = url;
        a.download = fileName;
        a.click();
        window.URL.revokeObjectURL(url);
    };
}());

saveBlob(file, 'test.zip');

This has helped me tremendously. Thank you!!

Thanks so much.

Thanks, a refactoring with anchor element deletion:

const fileUrl = window.URL.createObjectURL(blob)
const anchorElement = document.createElement('a')

anchorElement.href = fileUrl
anchorElement.download = 'Filename.ext'
anchorElement.style.display = 'none'

document.body.appendChild(anchorElement)

anchorElement.click()
anchorElement.remove()

window.URL.revokeObjectURL(fileUrl)

If you have only blob url:

var saveBlob = (function () {
    var a = document.createElement("a");
    document.body.appendChild(a);
    a.style = "display: none";
    return function (blob, fileName) {
        var url = window.URL.createObjectURL(blob);
        a.href = url;
        a.download = fileName;
        a.click();
        window.URL.revokeObjectURL(url);
    };
}());

fetch('blob:https://some.blob.url').then((response) => response.blob().then((b) => saveBlob(b, 'file.ext')));

Is there a data limit using this blob & url solution?
Eg. can a blob containing a 50MB zip, or a 5GB video be 'download' saved in the client in this way?
If not, is there a client-side way of saving v.large blobs?

@ChrisRoald, if you need to deal with data streams that are on the order of client RAM, you should *not* be creating Blobs that store the entire data stream in the first place, as they are inherently in-RAM objects.

Instead you should use showSaveFilePicker / FileSystemWritableFileStream — or for Firefox this ServiceWorker-based polyfill, pending proper support.

life saver!

thanks a bunch!