concat-stream

What is concat-stream?

The concat-stream npm package is a writable stream that concatenates data and calls a callback with the result. It can be used to collect stream data and concatenate it into a single buffer, string, or array. It is useful for collecting stream data from sources like HTTP requests, file reads, and other stream sources.

What are concat-stream's main functionalities?

Concatenate stream data into a buffer

This code sample demonstrates how to use concat-stream to read data from a file and concatenate it into a buffer. The buffer is then converted to a string and logged to the console.

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

const readStream = fs.createReadStream('file.txt');
const concatStream = concat(function(buffer) {
  console.log(buffer.toString());
});

readStream.pipe(concatStream);

Concatenate stream data into a string

This code sample shows how to use concat-stream to collect HTTP response data and concatenate it into a string. The string is then logged to the console.

const concat = require('concat-stream');
const http = require('http');

http.get('http://example.com', function(response) {
  response.pipe(concat(function(data) {
    console.log(data.toString());
  }));
});

Concatenate stream data into an array

This example demonstrates how to use concat-stream to collect data from a readable stream and concatenate it into an array. The resulting array is then logged to the console.

const concat = require('concat-stream');
const { Readable } = require('stream');

const arrayStream = Readable.from(['hello', ' ', 'world']);
const concatStream = concat({ encoding: 'array' }, function(array) {
  console.log(array);
});

arrayStream.pipe(concatStream);

Other packages similar to concat-stream

bl

The 'bl' (Buffer List) package is similar to concat-stream as it provides a storage object for collections of Node.js Buffers. It can be used to collect buffers and access them with a standard readable Buffer interface. It differs in its API and additional features like the ability to access data at specific indices without creating a new Buffer.

stream-buffers

The 'stream-buffers' package offers writable and readable stream implementations using a growable buffer. It is similar to concat-stream in that it allows for the collection of stream data, but it also provides more control over the buffer size and growth.

README

concat-stream

$ npm install concat-stream

then

var concat = require('concat-stream')
var fs = require('fs')
    
var read = fs.createReadStream('readme.md')
var write = concat(function(data) {})
    
read.pipe(write)

works with arrays too!

var write = concat(function(data) {})
write.write([1,2,3])
write.write([4,5,6])
write.end()
// data will be [1,2,3,4,5,6] in the above callback

works with buffers too! can't believe the deals!

var write = concat(function(data) {})
write.write(new Buffer('hello '))
write.write(new Buffer('world'))
write.end()
// data will be a buffer that toString()s to 'hello world' in the above callback

MIT LICENSE