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I want to decompress a GZIP string with JavaScript

I have this GZIPed string: H4sIAAAAAAAA//NIzcnJVyguSUzOzi9LLUrLyS/XUSjJSMzLLlZIyy9SSMwpT6wsVshIzSnIzEtXBACs78K6LwAAAA==
I created that with this website: http://www.txtwizard.net/compression
I have tried using pako to ungzip it.
import { ungzip } from 'pako';
const textEncoder = new TextEncoder();
const gzipedData = textEncoder.encode("H4sIAAAAAAAA//NIzcnJVyguSUzOzi9LLUrLyS/XUSjJSMzLLlZIyy9SSMwpT6wsVshIzSnIzEtXBACs78K6LwAAAA==");
console.log('gzipeddata', gzipedData);
const ungzipedData = ungzip(gzipedData);
console.log('ungziped data', ungzipedData);
The issue is that Pako throws the error: incorrect header check
What am I missing here?
A JSbin

The "H4sIAAAAAAAA//NIzcnJVyguSUzOzi9LLUrLyS/XUSjJSMzLLlZIyy9SSMwpT6wsVshIzSnIzEtXBACs78K6LwAAAA==" is a base64 encoded string, you first need to decode that into a buffer.
textEncoder.encode just encodes that base64 encoded string into a byte stream.
How to do that depend on whether you are in a browser or on nodejs.
node.js version
To convert the unzipped data to a string you further have use new TextDecoder().decode()
For node you will use Buffer.from(string, 'base64') to decode the base64 encoded string:
import { ungzip } from 'pako';
// decode the base64 encoded data
const gzipedData = Buffer.from("H4sIAAAAAAAA//NIzcnJVyguSUzOzi9LLUrLyS/XUSjJSMzLLlZIyy9SSMwpT6wsVshIzSnIzEtXBACs78K6LwAAAA==", "base64");
console.log('gzipeddata', gzipedData);
const ungzipedData = ungzip(gzipedData);
console.log('ungziped data', new TextDecoder().decode(ungzipedData));
browser version
In the browser, you have to use atob, and you need to convert the decoded data to an Uint8Array using e.g. Uint8Array.from.
The conversion I used was taken from Convert base64 string to ArrayBuffer, you might need to verify if that really works in all cases.
// decode the base64 encoded data
const gezipedData = atob("H4sIAAAAAAAA//NIzcnJVyguSUzOzi9LLUrLyS/XUSjJSMzLLlZIyy9SSMwpT6wsVshIzSnIzEtXBACs78K6LwAAAA==")
const gzipedDataArray = Uint8Array.from(gezipedData, c => c.charCodeAt(0))
console.log('gzipeddata', gzipedDataArray);
const ungzipedData = pako.ungzip(gzipedDataArray);
console.log('ungziped data', new TextDecoder().decode(ungzipedData));
<script src="https://cdnjs.cloudflare.com/ajax/libs/pako/2.0.4/pako.min.js"></script>

This string is base64-encoded.
You first need to decode it to a buffer:
const gzippedString = 'H4sIAAAAAAAA//NIzcnJVyguSUzOzi9LLUrLyS/XUSjJSMzLLlZIyy9SSMwpT6wsVshIzSnIzEtXBACs78K6LwAAAA==';
const gzippedBuffer = new Buffer(gzippedString, 'base64');
Then you can un(g)zip it:
const unzippedBuffer = ungzip(gzippedBuffer);
The result on ungzip is a Unit8Array. If you want to convert it back to a string you'll need to decode it again:
const unzippedString = new TextDecoder('utf8').decode(unzipped);

Issue in decoding in node js

I have a requirement where I need to encode data in "iso-8859-1" and then convert back it to readable string in node js.
In .Net env:
string encodedData = "VABpAG0AZQAgAHMAZQByAGUAaQBzAA==";
Encoding encoding = Encoding.GetEncoding("iso-8859-1"); // encoding in "iso-8859-1"
byte[] = decodedbuff = convert.FromBase64String(encodedData); // getting buffer
result = encoding.GetString(decodedbuff); //decoding
result = timesereis
In a similar way, I need to encode and decode in node js
In Node js(using iconvlite)
const data = "VABpAG0AZQAgAHMAZQByAGUAaQBzAA=="
const buffer = iconvlite.encode(data,'iso-8859-1');
const result = buffer.toString('utf8');
Here in result, I am getting "VABpAG0AZQAgAHMAZQByAGUAaQBzAA==" instead of decoded result

By using the following code you get your desired result
let buffer = new Buffer(data, 'base64');
let result = buff.toString('utf-8');
console.log("result: "+text)

How to decode the google cloud storage md5 hash to a string produced by hash generators in Node JS

Google cloud storage gives md5 hashes of objects encoded in base64. An example would be H0m5T/tigkNJLqL6+z9A7Q==. I've tried to convert it using btoa(), but that results in I9O{bCI."z{?#m instead of the expected b1f4f9a523e36fd969f4573e25af4540.
I'm getting the string with File.metadata.md5Hash described here
Is there any way to convert this base64 -> H0m5T/tigkNJLqL6+z9A7Q== to this string -> b1f4f9a523e36fd969f4573e25af4540 in node.js?
Code for reference:
async function getAllmd5()
{
const {Storage} = require('#google-cloud/storage');
const storage = new Storage();
var bucket = storage.bucket('example');
var [files] = await bucket.getFiles();
for (var i = 0; i < files.length; i++)
{
console.log(Buffer.from(files[i].metadata.md5Hash, 'base64').toString("ascii"))
}
}

It seems I had the wrong thought process.
I was thinking: get data -> get hash -> encode to base64
The problem was that isn't how that works.
What you need to instead is to: get data -> get hash AS base64. Usually a program will output it as hex, which is fine for most cases, but in Google's it was a base64 md5, different from a hex one.
An example of how to get the md5 hash as base64:
//The modules we need:
const { md5 } = require('crypto-md5');
const { fs } = require('fs');
var filename "example.txt";
//Read the file content
var filecontent = fs.readFileSync(path.join(__dirname, filename));
var hash = md5(filecontent, 'base64'); //Generate the md5 AS base64

JAVASCRIPT decode a base64string (which is an encoded zipfile) to a zipfile and get the zipfiles content by name

the question says it all, im receiving a base64 encoded ZIPFILE from the server, which I first want to decode to a ZIPFILE in memory and then get the ZIPFILES content, which is a json-file.
I tried to use JSZIP but im totally lost in this case ... the base64 string is received with javascript by a promise.
So my question in short is: How can I convert a base64 encoded ZIPFILE to a ZIPFILE in memory to get its contents.
BASE64 -> ZIPFILE -> CONTENT
I use this complicated process to save much space on my database. And I dont want to handle this process on server-side, but on clientside with JS.
Thanks in advance!

If anyone is interested in my solution to this problem read my answer right here:
I received the data in a base64-string format, then converted the string to a blob. Then I used the blob-handle to load the zipfile with the JSZip-Library. After that I could just grab the contents of the zipfile. Code is below:
function base64ToBlob(base64) {
let binaryString = window.atob(base64);
let binaryLen = binaryString.length;
let ab = new ArrayBuffer(binaryLen);
let ia = new Uint8Array(ab);
for (let i = 0; i < binaryLen; i++) {
ia[i] = binaryString.charCodeAt(i);
}
let bb = new Blob([ab]);
bb.lastModifiedDate = new Date();
bb.name = "archive.zip";
bb.type = "zip";
return bb;
}
To get the contents of the zipfile:
let blob = base64ToBlob(resolved);
let zip = new JSZip();
zip.loadAsync(blob).then(function(zip) {
zip.file("archived.json").async("string").then(function (content) {
console.log(content);
// content is the file as a string
});
}).catch((e) => {
});
As you can see, first the blob is created from the base64-string. Then the handle is given over to the JSZip loadAsync method. After that you have to set the name of the file which you want to retrieve from the zipfile. In this case it is the file called "archived.json". Now because of the async("string") function the file (file contents) are returned as a string. To further use the extracted string, just work with the content variable.

php base64_encode result not similar to javascript encode result

Code snippets:
php:
$shaVal = '59bc125840733ea828f42e276661b01e177f1414';
$enc = base64_encode(pack('H*', $shaVal));
echo $enc;
//prints => WbwSWEBzPqgo9C4nZmGwHhd/FBQ=
and in Javascipt I used buffer npm module
let Buffer = require('buffer').Buffer;
let shaVal = '59bc125840733ea828f42e276661b01e177f1414';
//function similar to php's pack() and returns binary data
let bData = Buffer.from(shaVal, 'hex').toString();
console.log('bData ', bData)
//encode with base64
let val64 = Buffer.from(bData, 'binary').toString('base64');
console.log('base 64 encode ', val64)
//prints => Wf0SWEBzPv0o/S4nZmH9Hhd/FBQ=
How can I get the exact same output printed by php?
Note: Both options showing binary data as Y�X#s>�(�.'fa�

It's because PHP pack returns string, where as javascript buffer returns Array.
This answer might help : https://stackoverflow.com/a/41962257/3086531