Learn node.js simple way - Stream concepts - Pipe streams

Pipe streams
Pipe is mechanism which works in a way that output of one stream would be input of other stream. It is chaining executions. Create a file called "pipe.js"

var fs = require("fs");

// Create a readable stream
var readerStream = fs.createReadStream('test.txt');

// Create a writable stream
var writerStream = fs.createWriteStream('output.txt');

// Pipe the read and write operations
// read test.txt and write data to output.txt
readerStream.pipe(writerStream);

console.log("Program Ended");

Run the program.

node pipe.js

Check the output.txt file.

Chaining the Streams

Chaining is a mechanism to get the output of one stream to another stream and create a chain of multiple stream operations.

In the below example, we read the file and create a zip and write the content into zip file.

var fs = require("fs");
var zlib = require('zlib');

// Compress the file input.txt to input.txt.gz
fs.createReadStream('test.txt')
   .pipe(zlib.createGzip())
   .pipe(fs.createWriteStream('test.txt.gz'));
  
console.log("File Compressed.");

Run the program and check the output.

Decompress the file

var fs = require("fs");
var zlib = require('zlib');

// Decompress the file input.txt.gz to input.txt
fs.createReadStream('test.txt.gz')
   .pipe(zlib.createGunzip())
   .pipe(fs.createWriteStream('test.txt'));
  
console.log("File Decompressed.");

Run the program and check the output.