I'm fairly new to JavaScript. I'm currently working on an algorithm that deflates in Java and inflates in javascript. For the most part, I have heard that pako.js is a good tool to use for decompression but I'm having problems implementing it. I created a function in JavaScript that passes the base64 string as a parameter.

function decompressHtml(html){

                var compressedData = atob(html);
                var charData = compressedData.split('').map(function(x){return x.charCodeAt(0);});
                var binData = new Uint8Array(charData);
                var inflated = '';


                try {
                  inflated = pako.inflate(binData);

                } catch (err) {
                  console.log(err);
                }

                return inflated;

        }

It always returns an error that says that pako is not properly defined. Is there a specific script tag/s that need to be inserted in order to define pako? I realise this may be a simple question to answer but I'm not sure of the answer.

I'm fairly new to JavaScript. I'm currently working on an algorithm that deflates in Java and inflates in javascript. For the most part, I have heard that pako.js is a good tool to use for decompression but I'm having problems implementing it. I created a function in JavaScript that passes the base64 string as a parameter.

function decompressHtml(html){

                var compressedData = atob(html);
                var charData = compressedData.split('').map(function(x){return x.charCodeAt(0);});
                var binData = new Uint8Array(charData);
                var inflated = '';


                try {
                  inflated = pako.inflate(binData);

                } catch (err) {
                  console.log(err);
                }

                return inflated;

        }

It always returns an error that says that pako is not properly defined. Is there a specific script tag/s that need to be inserted in order to define pako? I realise this may be a simple question to answer but I'm not sure of the answer.

• javascript
• html
• zlib
• compression

• 1 Have you...included pako on the page? – VLAZ Commented Aug 10, 2016 at 20:18
• I have actually..that's the confusing part – atsnam Commented Aug 12, 2016 at 1:40
• You can include the pako from CDN jsdelivr.com/package/npm/pako – Sergey Ponomarev Commented Feb 25, 2024 at 14:47

3 Answers 3

1. Download pako.js or pako.min.js from official pako github page

2. Include the downloaded file in your html as follows:

   <script type="text/javascript" src="pako.js"></script>

Sample code:

var input = "test string";
var output = pako.gzip(input,{ to: 'string' });
alert("compressed gzip string - " + output);
var originalInput = pako.ungzip(output,{ to: 'string' });
alert("uncompressed string - " + originalInput);

This will help you

Decompress

const input = new Uint8Array(res);
const restored = JSON.parse(pako.inflate(input, { to: 'string'}));
console.log(restored)

Compress

const input = new Uint8Array(res);
const output = pako.deflate(input);
console.log(output)

Pako expects to be bound to an object named global, which is (as of Chrome 118) undefined in the browser. You can create the global object and make Pako happy by putting this in a script somewhere before Pako's script tag.

if (!window.global) window.global = window;