fflate

High performance (de)compression in an 8kB package

features

特定のファイルだけ取り出して解凍できる

worker support

streaming support

圧縮/解凍を逐次実行できる

web stream APIではなく、独自のAPI

code:ts

import {

AsyncZipDeflate,

Zip,

ZipDeflate,

ZipPassThrough,

} from "npm:fflate@0.8";

export class ZipStream extends TransformStream<File, Uint8Array> {

constructor(

writableStrategy?: QueuingStrategy<File>,

readableStrategy?: QueuingStrategy<Uint8Array>,

) {

const zip = new Zip();

super(

{

start: (controller) => {

zip.ondata = (err, data, final) => {

if (err) controller.error(err);

else {

controller.enqueue(data);

if (final) controller.terminate();

}

};

},

transform: async (file) => {

const filename = file.webkitRelativePath || file.name;

const ext = filename.slice(filename.lastIndexOf(".") + 1);

const zippedFileStream = incompressibleTypes.has(ext)

? new ZipPassThrough(filename)

: file.size > largeFileSize

? new AsyncZipDeflate(filename, { level: 9 })

: new ZipDeflate(filename, { level: 9 });

zippedFileStream.mtime = file.lastModified;

zip.add(zippedFileStream);

for await (const chunk of file.stream()) {

zippedFileStream.push(chunk);

}

zippedFileStream.push(new Uint8Array(), true);

},

flush: () => {

zip.end();

},

},

writableStrategy,

readableStrategy,

);

}

}

const incompressibleTypes = new Set([

"zip",

"gz",

"png",

"jpg",

"jpeg",

"pdf",

"doc",

"docx",

"ppt",

"pptx",

"xls",

"xlsx",

"heic",

"heif",

"7z",

"bz2",

"rar",

"gif",

"webp",

"webm",

"mp4",

"mov",

"mp3",

"aifc",

]);

const largeFileSize = 500000;