request(url).pipe(fs.createWriteStream(filename)).pipe(writestream);
与此相同:
var fileStream = fs.createWriteStream(filename);request(url).pipe(fileStream);fileStream.pipe(writestream);
因此,问题在于您正在尝试
.pipe彼此
WriteStream融合
WriteStream。

request(url).pipe(fs.createWriteStream(filename)).pipe(writestream);
与此相同:
var fileStream = fs.createWriteStream(filename);request(url).pipe(fileStream);fileStream.pipe(writestream);
因此,问题在于您正在尝试
.pipe彼此
WriteStream融合
WriteStream。