使用ServiceWorker，通过下载NPM registry中的tgz包，实现前端下载、UNGZIP、UNTar一条龙分发静态文件

UsingNPMRegistryAsCDN.serviceworker.js

import tarball from "./tarball.js"
import { ungzip } from "pako"
import CacheDb from "@chenyfan/cache-db"
const defaultResponse = `<a href="/?package_name=chenyfan-os&version=0.0.0-r26&path=img%20(4).png">Example</a>`
const genTarUrl = (package_name, version) => {
    //const prefix = "https://registry.npmjs.org/"
    //const prefix = "https://mirrors.cloud.tencent.com/npm/"
    //const prefix = "https://registry.npmmirror.com/"
    //const prefix = "https://mirrors.huaweicloud.com/repository/npm/" //CORS限制
    const prefix = "https://npmreg.proxy.ustclug.org/"
    return prefix + package_name + "/-/" + package_name + "-" + version + ".tgz"
}

const handleNPMRequest = async (request) => {
    const url = new URL(request.url)
    const npm_package = url.searchParams.get("package_name")
    const npm_version = url.searchParams.get("version") || "latest"
    const npm_path = url.searchParams.get("path") || "/"
    if (!npm_package) return new Response(defaultResponse, { status: 400, headers: { "Content-Type": "text/html" } })
    const PackageCache = new CacheDb("npmPackage")
    const ProviderCache = new CacheDb(`npmProvider@${npm_package}@${npm_version}`)
    let getProviderExist = await ProviderCache.read(`package.json`).then(res => res ? true : false)
    if (!getProviderExist) {
        let getPackage = await PackageCache.read(`${npm_package}@${npm_version}`)
        if (!getPackage) {
            getPackage = await fetch(genTarUrl(npm_package, npm_version)).then(res => res.arrayBuffer())
            await PackageCache.write(`${npm_package}@${npm_version}`, getPackage)
        }
        const ungziped = ungzip(new Uint8Array(getPackage))
        const ungzipedBlob = new Blob([ungziped], { type: "application/gzip" })
        let tarReader = new tarball.TarReader()
        const unTaredList = await tarReader.readFile(ungzipedBlob)
        for (let file in unTaredList) {
            await ProviderCache.write(unTaredList[file].name.replace("package/", ""), tarReader.getFileBinary(unTaredList[file].name))
        }
    }
    return new Response(await ProviderCache.read(npm_path, { type: "arrayBuffer" }), {
        status: 200, headers: {
            "content-type": ((suffix) => {
                switch (suffix) {
                    case "json":
                        return "application/json"
                    case "js":
                        return "application/javascript"
                    case "css":
                        return "text/css"
                    case "png":
                        return "image/png"
                    case "jpg":
                        return "image/jpeg"
                    case "html":
                        return "text/html"
                    default:
                        return "text/plain"
                }
            })(npm_path.split(".").pop().toLowerCase())
        }
    })
}
addEventListener("fetch", (event) => {
    event.respondWith(handleNPMRequest(event.request))
})