CODEWITHSUNDEEP
javascriptstringencryptioncompression
HenryChinaski
HenryChinaski

Reputation: 167

Is there a way to compress a long string to a smaller one and vise versa by code?

I am working on a plugin for an existing web-based tool in JavaScript. We are collecting data and store it in a string like this: "2.545,3.552,8.568;2.553,9.898,6.542;..." and so on.

The problem is, that we reach an export limit of 64k characters too fast. I wanted to ask - and excuse me if it is a dumb question - if someone knows of an algorithm or method we could use to compress the string before we export it. I am sure that it is technically possible but it certainly exceeds my skills as a programmer.

Thanks for any tips, link or suggestion.

Upvotes: 6

Views: 13066

Answers (3)

Michel
Michel

Reputation: 97

You can use fflate to Zip/Unzip a string.

In your HTML code add :

<script src="https://unpkg.com/[email protected]"></script>

In your JavaScript code add :

function zip_encode(str) {
    const ascii = encodeURIComponent(str)
    const array = new TextEncoder().encode(ascii)
    const zip = fflate.deflateSync(array, {level: 9})
    return window.btoa(String.fromCharCode(...zip))
}

function zip_decode(base64) {
    const raw = window.atob(base64)
    const array = Uint8Array.from(raw, c => c.charCodeAt(0))
    const unzip = fflate.inflateSync(array)
    const ascii = new TextDecoder().decode(unzip)
    return decodeURIComponent(ascii)
}

This code should work efficiently for most use cases.

function zip_encode(str) {
    const ascii = encodeURIComponent(str)
    const array = new TextEncoder().encode(ascii)
    const zip = fflate.deflateSync(array, {level: 9})
    return window.btoa(String.fromCharCode(...zip))
}

function zip_decode(base64) {
    const raw = window.atob(base64)
    const array = Uint8Array.from(raw, c => c.charCodeAt(0))
    const unzip = fflate.inflateSync(array)
    const ascii = new TextDecoder().decode(unzip)
    return decodeURIComponent(ascii)
}

// Example usage
const example = "Hello, this is a sample '😎' icon!"
console.log("Original String:", example)
// Original String: Hello, this is a sample '😎' icon!

const compressed = zip_encode(example)
console.log("Compressed Data:", compressed)
// Compressed Data: 80jNyclXNXJWNTIoycgsBlJgIhGIixNzC3JSgQx1VTcDVUs3VUsLVQtXdZCS5Pw8RQA=

const example_decompressed = zip_decode(compressed)
console.log("Decompressed String:", example_decompressed)
// Decompressed String: Hello, this is a sample '😎' icon!
<script src="https://unpkg.com/[email protected]"></script>

Upvotes: 4

Markus Safar
Markus Safar

Reputation: 6580

I would suggest you use a dedicated Web Worker for this. There is a pretty good explanation on Using Web Worker on the mozilla developers page.

Upvotes: 0

Will
Will

Reputation: 3241

lz-string looks like it will work.

var string = "2.545,3.552,8.568;2.553,9.898,6.542";
alert("Size of sample is: " + string.length);
var compressed = LZString.compress(string);
alert("Size of compressed sample is: " + compressed.length);
string = LZString.decompress(compressed);
alert("Sample is: " + string);
<script src="https://cdn.jsdelivr.net/gh/pieroxy/lz-string/libs/lz-string.js"></script>

Upvotes: 7

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