text compression (JavaScript)

sample.js

let txt = crypto.randomUUID().repeat(10);
console.log(txt.length, "characters (uncompressed)");

let data = await compress(txt);
console.log(data.byteLength, "bytes (compressed)");
console.log(data.toBase64().length, "characters (compressed, Base64)");

/**
 * @param {string} txt
 * @returns {Promise<Uint8Array>}
 */
async function compress(txt) {
	let stream = txt2stream(txt)
		.pipeThrough(new TextEncoderStream())
		.pipeThrough(new CompressionStream("gzip"));
	let blob = await new Response(stream).blob();
	return blob.bytes();
}

/** @param {string} txt */
// XXX: this becomes obsolete once `ReadableStream.from` is widely available
function txt2stream(txt) {
	return new ReadableStream({
		start(controller) {
			controller.enqueue(txt);
			controller.close();
		},
	});
}