javascript base64到blob #js＃base64

Posted 2021-05-03

base64ToBlob = function(base64, mime) {
    mime = mime || '';
    var sliceSize = 1024;
    var byteChars = window.atob(base64);
    var byteArrays = [];

    for (var offset = 0, len = byteChars.length; offset < len; offset += sliceSize) {
        var slice = byteChars.slice(offset, offset + sliceSize);

        var byteNumbers = new Array(slice.length);
        for (var i = 0; i < slice.length; i++) {
            byteNumbers[i] = slice.charCodeAt(i);
        }

        var byteArray = new Uint8Array(byteNumbers);

        byteArrays.push(byteArray);
    }

    return new Blob(byteArrays, { type: mime });
}