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by molsson 612 days ago
process.stdout._handle.setBlocking(true)

...is a bit brutal but works. Draining the stream before exiting also kind of works but there are cases where drain will just permanently block.

async function drain(stream) { return new Promise((resolve) => stream.on('drain', resolve)) }
2 comments
jitl 612 days ago
When you want to await a single instance of a Node EventEmitter, please use `stream.once('drain', (err) => ...)` so you don't leak your listener callback after the promise resolves.
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yladiz 612 days ago
Which cases will it permanently block?
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jitl 612 days ago
The writable stream will only emit 'drain' if the buffer fills past the limit. In that case, a prior call to `writable.write(...)` would return `false` indicating you should wait for drain before calling write again. Even if your code can't access the return value for the last writable.write call, you can check `if (writable.writableNeedDrain) { ...` to decide to wait for drain.

This program will run forever, since we never write to stdout, stdout never "drains":

    setInterval(() => console.error("stderr: ", new Date().toISOString()), 5_000)
    process.stdout.once("drain", () => {
      console.error("stderr: stdout.once.drain, exit")
      process.exit(0)
    })
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