Nodejs - spawn.stdout 和 process.stdout 之间的区别

Question

玩弄 child_process，我想将生成的 cp 输出通过管道传输到自定义流。

我不明白为什么在第一种情况下管道不起作用，而在第二种情况下管道不起作用。

预设

const cp = require('child_process');
const process = require('process');
const stream = require('stream');

var writable = new stream.Writable();
writable._write = function (data) {
    console.log(data.toString());
};

不起作用

var spawnedProcess = cp.spawn('ls', [], {
    stdio: [process.stdin, process.stdout, process.stderr] 
});
process.stdout.pipe(writable);

输出登录到终端但不通过管道传输。

有效

var spawnedProcess = cp.spawn('ls', [], {});
spawnedProcess.stdout.pipe(writable);

管道输出到 writable。

Answer 1

文档说 process.stdout is only a Writable stream so you can't pipe from it. It's weird it doesn't throw an Error: Cannot pipe. Not readable. though. Also, cp.stdout 是一个可读流，因此它按应有的方式进行管道传输。

Nodejs - spawn.stdout 和 process.stdout 之间的区别

Nodejs - difference between spawn.stdout and process.stdout

child-process

node.js

预设

不起作用

有效