Fix tags path build (#21)

* Fix tags path
* Service worker

src/lib/components/elements/Tag.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+	import { base } from '$app/paths'
 	import { slug } from 'github-slugger'
 
 	export let text
@@ -8,7 +9,7 @@
 </script>
 
 <a
-	href={'/tags/' + url}
+	href={base + '/tags/' + url}
 	class="rounded-md border bg-arkGray7 px-1 text-sm font-medium hover:bg-arkGray5 {classes}"
 >
 	{text}

src/service-worker.ts

@@ -0,0 +1,85 @@
+/// <reference types="@sveltejs/kit" />
+/// <reference types="@sveltejs/kit" />
+/// <reference no-default-lib="true"/>
+/// <reference lib="esnext" />
+/// <reference lib="webworker" />
+
+import { build, files, version } from '$service-worker'
+
+// Create a unique cache name for this deployment
+const CACHE = `cache-${version}`
+
+const ASSETS = [
+	...build, // the app itself
+	...files, // everything in `static`
+]
+
+self.addEventListener('install', (event) => {
+	// Create a new cache and add all files to it
+	async function addFilesToCache() {
+		const cache = await caches.open(CACHE)
+		await cache.addAll(ASSETS)
+	}
+
+	event.waitUntil(addFilesToCache())
+})
+
+self.addEventListener('activate', (event) => {
+	// Remove previous cached data from disk
+	async function deleteOldCaches() {
+		for (const key of await caches.keys()) {
+			if (key !== CACHE) await caches.delete(key)
+		}
+	}
+
+	event.waitUntil(deleteOldCaches())
+})
+
+self.addEventListener('fetch', (event) => {
+	// ignore POST requests etc
+	if (event.request.method !== 'GET') return
+
+	async function respond() {
+		const url = new URL(event.request.url)
+		const cache = await caches.open(CACHE)
+
+		// `build`/`files` can always be served from the cache
+		if (ASSETS.includes(url.pathname)) {
+			const response = await cache.match(url.pathname)
+
+			if (response) {
+				return response
+			}
+		}
+
+		// for everything else, try the network first, but
+		// fall back to the cache if we're offline
+		try {
+			const response = await fetch(event.request)
+
+			// if we're offline, fetch can return a value that is not a Response
+			// instead of throwing - and we can't pass this non-Response to respondWith
+			if (!(response instanceof Response)) {
+				throw new Error('invalid response from fetch')
+			}
+
+			if (response.status === 200) {
+				cache.put(event.request, response.clone())
+			}
+
+			return response
+		} catch (err) {
+			const response = await cache.match(event.request)
+
+			if (response) {
+				return response
+			}
+
+			// if there's no cache, then just error out
+			// as there is nothing we can do to respond to this request
+			throw err
+		}
+	}
+
+	event.respondWith(respond())
+})