JSFiddle - React, Tailwind, and code Playground

HTML

<button onclick="download_data()">Download</button>

JavaScript

function download_data(){
	var data = new Int8Array(1);
	data[0] = 42;
  download([data],"test.bin");
}

var download = (function () {
    var dwnld = document.createElement("a");
    document.body.appendChild(dwnld);
    dwnld.style = "display: none";
    return function (data, name) {
        var blob = new Blob(data, {type: "octet/stream"}),
        url = window.URL.createObjectURL(blob);
        dwnld.href = url;
        dwnld.download = name;
        dwnld.click();
        window.URL.revokeObjectURL(url);
    };
}());