blob与base64

[xlearns]

// base64 -> blob
function dataURLtoBlob(dataurl) {
    var arr = dataurl.split(","),
        mime = arr[0].match(/:(.*?);/)[1],
        bstr = atob(arr[1]),
        n = bstr.length,
        u8arr = new Uint8Array(n);
    while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
    }
    return new Blob([u8arr], {
        type: mime
    });
}

//download
function downloadFile(url, name = "What's the fuvk") {
    var a = document.createElement("a");
    a.setAttribute("href", url);
    a.setAttribute("download", name);
    a.setAttribute("target", "_blank");
    let clickEvent = document.createEvent("MouseEvents");
    clickEvent.initEvent("click", true, true);
    a.dispatchEvent(clickEvent);
}

function downloadFileByBase64(base64, name) {
    var myBlob = dataURLtoBlob(base64);
    var myUrl = URL.createObjectURL(myBlob);
    downloadFile(myUrl, name);
}