end-of-stream

What is end-of-stream?

The end-of-stream npm package is designed to help developers handle the end or error conditions of a stream more easily. It provides a simple way to execute a callback when a stream has finished or failed, making it easier to manage streams in Node.js applications.

What are end-of-stream's main functionalities?

Callback on stream end

This feature allows you to execute a callback function when the stream ends or encounters an error. The code sample demonstrates how to use end-of-stream with a file read stream.

const eos = require('end-of-stream');
const fs = require('fs');

const readStream = fs.createReadStream('file.txt');
eos(readStream, function(err) {
  if (err) return console.log('Stream had an error or closed early');
  console.log('Stream has ended');
});

Promise support

This feature demonstrates how to use end-of-stream with promises, providing a more modern approach to handling stream completion. It uses the `promisify` utility from Node.js to convert the eos callback pattern into a promise.

const eos = require('end-of-stream');
const fs = require('fs');
const { promisify } = require('util');

const eosPromise = promisify(eos);

const readStream = fs.createReadStream('file.txt');
eosPromise(readStream).then(() => console.log('Stream has ended')).catch(err => console.log('Stream had an error or closed early'));

Other packages similar to end-of-stream

pump

Pump is a package that not only listens for the end of streams but also helps to pipe streams together and handles cleanup in case of a stream ending prematurely. It's more comprehensive than end-of-stream as it also manages the flow between streams.

README

end-of-stream

A node module that calls a callback when a readable/writable/duplex stream has completed or failed.

npm install end-of-stream

Usage

Simply pass a stream and a callback to the eos. Both legacy streams, streams2 and stream3 are supported.

var eos = require('end-of-stream');

eos(readableStream, function(err) {
  // this will be set to the stream instance
	if (err) return console.log('stream had an error or closed early');
	console.log('stream has ended', this === readableStream);
});

eos(writableStream, function(err) {
	if (err) return console.log('stream had an error or closed early');
	console.log('stream has finished', this === writableStream);
});

eos(duplexStream, function(err) {
	if (err) return console.log('stream had an error or closed early');
	console.log('stream has ended and finished', this === duplexStream);
});

eos(duplexStream, {readable:false}, function(err) {
	if (err) return console.log('stream had an error or closed early');
	console.log('stream has finished but might still be readable');
});

eos(duplexStream, {writable:false}, function(err) {
	if (err) return console.log('stream had an error or closed early');
	console.log('stream has ended but might still be writable');
});

eos(readableStream, {error:false}, function(err) {
	// do not treat emit('error', err) as a end-of-stream
});

License

MIT

Related

end-of-stream is part of the mississippi stream utility collection which includes more useful stream modules similar to this one.