Node.js Stream Close Testing

nodejs-stream-close-testing.js

const fs = require('fs');
const stream = require('stream');

let readStream,
	passThrough,
	writeStream,
	transform;

const inputPath = '/tmp/input.txt';
const outputPath = '/tmp/output.txt';
function setup() {
	fs.writeFileSync(inputPath, "This is the input.");
	fs.writeFileSync(outputPath, "");

	readStream = fs.createReadStream(inputPath);
	passThrough = new stream.PassThrough({allowHalfOpen: false});
	writeStream = fs.createWriteStream(outputPath);
	transform = new stream.Transform({
		allowHalfOpen: false,
		transform: (chunk, encoding, cb) => cb(null, chunk)
	});
	addDebugEvents(readStream, 'read');
	addDebugEvents(writeStream, 'write');
	addDebugEvents(passThrough, 'passThrough');
	addDebugEvents(transform, 'transform');
}

function test1(cb) {
	console.log("Test 1: Read | Write\n");
	const rwPipeStream = readStream.pipe(writeStream);
	addDebugEvents(rwPipeStream, 'rwPipe');
	readStream.on('close', () => {
		console.log("Test 1 Complete.\n");
		cb();
	});
}

function test2(cb) {
	console.log("Test 2: Transform | Write\n");
	const pipeResult = transform.pipe(writeStream);
	addDebugEvents(pipeResult, 'piped');
	transform.on('close', () => {
		console.log("Test 2 Complete.\n");
		cb();
	});
	transform.end('hello world');
}

function addDebugEvents(stream, name) {
	['close', 'drain', 'error', 'finish', 'pipe', 'unpipe', 'data', 'end', 'readable']
		.map(eventName => stream.on(eventName, () => console.log(`${name}-${eventName}`)))
}

// Run it!
setup();
test1(() => setTimeout(() => {
	console.log("Waited for remaining Test 1 stream events, done!\n");
	setup();
	test2();
}, 1000));

resutls.txt

Test 1: Read | Write

write-pipe
read-data
read-readable
read-end
write-finish
write-unpipe
rwPipe-unpipe
rwPipe-finish
read-close
Test 1 Complete.

write-close
rwPipe-close
Waited for remaining Test 1 stream events, done!

Test 2: Transform | Write

write-pipe
transform-data
transform-readable
transform-finish
transform-end
read-data
write-finish
write-unpipe
piped-unpipe
piped-finish
read-readable
read-end
write-close
piped-close
read-close