纯js实现文件下载并重命名功能

/**
 * 获取 blob
 * @param  {String} url 目标文件地址
 * @return {cb} 
 */
function getBlob(url,cb) {
        var xhr = new XMLHttpRequest();
        xhr.open(‘GET‘, url, true);
        xhr.responseType = ‘blob‘;
        xhr.onload = function() {
                if (xhr.status === 200) {
                    cb(xhr.response);
                }
        };
        xhr.send();
}

/**
 * 保存
 * @param  {Blob} blob     
 * @param  {String} filename 想要保存的文件名称
 */
function saveAs(blob, filename) {
    if (window.navigator.msSaveOrOpenBlob) {
            navigator.msSaveBlob(blob, filename);
    } else {
            var link = document.createElement(‘a‘);
            var body = document.querySelector(‘body‘);

            link.href = window.URL.createObjectURL(blob);
            link.download = filename;

            // fix Firefox
            link.style.display = ‘none‘;
            body.appendChild(link);
            
            link.click();
            body.removeChild(link);

            window.URL.revokeObjectURL(link.href);
    };
}

/**
 * 下载
 * @param  {String} url 目标文件地址
 * @param  {String} filename 想要保存的文件名称
 */
function download(url, filename) {
    getBlob(url, function(blob) {
        saveAs(blob, filename);
    });
};