Process suddenly terminating with exit code 0

[papb]

I was experimenting with pEvent.iterator with fs.createReadStream. See this very simple example:

// what.js
const pEvent = require('p-event');
const fs = require('fs');

(async () => {
	try {
		console.log('A');
		const asyncIterator = pEvent.iterator(fs.createReadStream('.npmrc'), 'data');
		console.log('B');
		for await (const event of asyncIterator) {
			console.log('C', event.toString());
		}
		console.log('D');
	} catch {
		console.log('E');
	}
})();

Executing node what.js && echo success gives:

A
B
C package-lock=false
success

It does not log D nor E, and even exits with code 0! Do you have any idea what is going on here?

[sindresorhus]

What Node.js version? Can you try with the absolute latest Node.js version?

[papb]

Sorry I didn't include the version. It's node 12.18.0, on windows. I will try with the absolute latest soon.

[papb]

Hi @sindresorhus, I just tried all 9 possible combinations of Windows, Linux and Mac with Node 14, 12, and 10. Each one of them gave the exact same output as above...

😮

(tried with github actions)

[papb]

Is it even possible that this behavior is p-event's fault? Looks like a really weird bug with for await to me... Or with fs.createReadStream... But I can't imagine how p-event would be causing this...

[sindresorhus]

I have no idea, to be honest, but why are you even using p-event for this? Node.js readable streams can be iterated natively with for-await.

[papb]

@sindresorhus Sorry for the delay. Indeed I could be iterating natively instead, thanks for the reminder! However, I just got into a similar situation, without Node.js readable streams. Here is a minimal example:

// what.js
const pEvent = require('p-event');
const Emittery = require('emittery');
const emitter = new Emittery();

(async () => {
	setTimeout(() => {
		emitter.emit('data', 'foobar');
	}, 500);

	try {
		console.log('A');
		const asyncIterator = pEvent.iterator(emitter, 'data');
		console.log('B');
		for await (const event of asyncIterator) {
			console.log('C', event);
		}
		console.log('D');
	} catch {
		console.log('E');
	}
})();

Again, executing node what.js && echo success gives:

A
B
C foobar
success

In this example, I expected the process to hang indefinitely after printing C foobar.

[papb]

This is a little scary... 😮

[papb]

For now, I am working around it with:

const keepAlive = setTimeout(() => {}, (2 ** 31) - 1);
// ...
clearTimeout(keepAlive);

[EvanHahn]

I can no longer reproduce this on the latest version. Here's a modified version of the original report that works fine for me:

import { pEventIterator } from "p-event";
import * as fs from "node:fs";

(async () => {
  try {
    console.log("A");
    const asyncIterator = pEventIterator(
      fs.createReadStream("package.json"),
      "data",
      {
        resolutionEvents: ["close"],
      },
    );
    console.log("B");
    for await (const event of asyncIterator) {
      console.log("C", event.length);
    }
    console.log("D");
  } catch {
    console.log("E");
  }
})();

This logs:

A
B
C 6113
D

I think this issue can be closed?