node.js - nodejs 先写入文件createWriteStream，再读取文件内容createReadStream，获取不到信息

Question

request(url).pipe(fs.createWriteStream(fpath));
                            
var bu = fs.createReadStream(fpath, {start: 0, end: 262});
dlog(bu);

我先写入文件，再读取里面的东西，但是createReadStream读取不到东西。这是为什么？是因为上面的操作是异步进行的吗？如果是，那应该如何获取呢？

Answer 1

stream is an asynchronous operation. You will not get the result if you write it synchronously. So:

request(url)
    .pipe(fs.createWriteStream(fpath))
    .on('close', function() {
        var bu = fs.createReadStream(fpath, {start: 0, end: 262});
        bu.on('data', function(chunk) {
            console.log(chunk.toString());//这是结果
        });
    });

See more documentation: fs