Node.js zlib.gunzip() Method

The zlib.gunzip() method is an inbuilt application programming interface of the Zlib module which is used to decompress a chunk of data.

Syntax:

zlib.gunzip( buffer, options, callback )

Parameters: This method accepts three parameters as mentioned above and described below:

• buffer: It can be of type Buffer, TypedArray, DataView, ArrayBuffer, and string.
• options: It is an optional parameter that holds the zlib options.
• callback: It holds the callback function.

Return Value: It returns the chunk of data after decompression.

Below examples illustrate the use of zlib.gunzip() method in Node.js:

Example 1:

// Node.js program to demonstrate the
// gunzip() method

// Including zlib module
const zlib = require("zlib");

// Declaring input and assigning
// it a value string
var input = "Geek";

// Calling gzip method
zlib.gzip(input, (err, buffer) => {

  // Calling gunzip method
 zlib.gunzip(buffer, (err, buffer) => {

    console.log(buffer.toString('utf8'));

    });
 });

console.log("Data Decompressed...");

Output:

Data Decompressed...
Geek

Example 2:

// Node.js program to demonstrate the
// gunzip() method

// Including zlib module
const zlib = require("zlib");

// Declaring input and assigning
// it a value string
var input = "Geek";

// Calling gzip method
zlib.gzip(input, (err, buffer) => {

  // Calling gunzip method
 zlib.gunzip(buffer, (err, buffer) => {

    console.log(buffer.toString('hex'));

    });
 });

console.log("Data Decompressed...");

Output:

Data Decompressed...
4765656b

Reference: https://nodejs.org/api/zlib.html#zlib_zlib_gunzip_buffer_options_callback