test_stream_transform_async_callback.cjs
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test_stream_transform_async_callback.cjs
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	const { Transform } = require('node:stream');

	async function main() {
	let output = '';

	const tr = new Transform({
	transform(chunk, encoding, cb) {
	Promise.resolve().then(() => {
	cb(null, chunk.toString('utf8').toUpperCase());
	});
	},
	});

	tr.on('data', (chunk) => {
	output += chunk.toString('utf8');
	});

	const finished = new Promise((resolve, reject) => {
	tr.on('finish', resolve);
	tr.on('error', reject);
	});

	tr.write('abc');
	tr.end();
	await finished;

	if (output !== 'ABC') {
	throw new Error(`expected "ABC", got ${JSON.stringify(output)}`);
	}

	console.log('stream Transform async callback preserves receiver state');
	}

	main().catch((err) => {
	console.error(err && err.stack ? err.stack : String(err));
	process.exit(1);
	});