nodejs下载文件

downfile.js

    function downloadFile(url) {
        var httpClient = url.slice(0,5) === "https"? https:http;

        httpClient.get(url,function(response) {
            var RegFileName = new RegExp();
            RegFileName.compile(".*%2F(.*?)$");
            var fileName = RegFileName.exec(url)[1];
            console.log(fileName);
            if(fileName) {
                var writer = fs.createWriteStream(resPath+fileName);
                response.pipe(writer);
            }
        })
    }