Javascript gzip decompress in browser

I feel that there should be a way to use the browser's native functionality to un-gzip. If I am wrong can someone explain why this browser functionality is not exposed as a javascript API?

No, there shouldn't be, unless it is in w3c standard and it is not. The only standard which says something about gzip compression is an HTTP standard.

I really believe it won't become standard because there are thousands of algorithms (for compression, encryption, etc.) which you may want to use and browsers cannot handle them all; it would also be unfair to create interfaces for one algorithm while not creating them for another.

HTTP protocol is a kind of exception. The compression here is done to make the life of millions of people easier. The HTTP is a bottle neck in web performance, so as long as the compression is available there I cannot imagine any case when you elsewhere need to use a compression in JavaScript. The only case I know is compressing items in a localStorage / indexedDB, but even there gzip won't work because it is not producing UTF-16 output.

That is why this is not in the standard and this is why it most likely won't appear there.

Your particular case is a server side implementation error. Using compressed output without a proper header really smells. Either don't use the compression or do it right.

And is there a way to un-gzip a file in javascript without adding an additional library?

Actually other than that there is a possible solution: create a browser extension which injects a proper header in a server response and you won't need a library but will need to distribute the extension to the users. Could be even worse, but still may work.

const readableStream = await fetch('lorem.txt').then(
  (response) => response.body
);
const compressedReadableStream = readableStream.pipeThrough(
  new CompressionStream('gzip')
);

const decompressedReadableStream = compressedReadableStream.pipeThrough(
  new DecompressionStream('gzip')
);

new DecompressionStream(format)

const ds = new DecompressionStream('gzip');
const decompressedStream = blob.stream().pipeThrough(ds);

Does browser decompress gzip?

Do any browsers not support gzip?

How does browser gzip work?

How do I gzip a JavaScript file?