Port application from Next.js to Nuxt

Nuxt is based on Vue.js and I find their building blocks to be much
neater compared to the React based Next.js.

server/web-push.ts

@@ -0,0 +1,56 @@
+import { readFile, writeFile } from "node:fs/promises";
+import webPush from "web-push";
+
+webPush.setVapidDetails(
+	"mailto:webmaster@hornwitser.no",
+	process.env.NUXT_PUBLIC_VAPID_PUBLIC_KEY!,
+	process.env.NUXT_VAPID_PRIVATE_KEY!,
+)
+
+export async function sendPush(title: string, body: string) {
+	const payload = JSON.stringify({ title, body });
+	let subscriptions: PushSubscriptionJSON[];
+	try {
+		subscriptions = JSON.parse(await readFile("push-subscriptions.json", "utf-8"));
+	} catch (err: any) {
+		if (err.code !== "ENOENT") {
+			console.log(`Dropping "${payload}", no push subscribers`);
+			return;
+		}
+		subscriptions = [];
+	}
+	console.log(`Sending "${payload}" to ${subscriptions.length} subscribers`);
+	const removeIndexes = [];
+	for (let index = 0; index < subscriptions.length; index += 1) {
+		const subscription = subscriptions[index];
+		try {
+			await webPush.sendNotification(
+				subscription as webPush.PushSubscription,
+				payload,
+				{
+					TTL: 3600,
+					urgency: "high",
+				}
+			)
+		} catch (err: any) {
+			console.error("Received error sending push notice:", err.message, err?.statusCode)
+			console.error(err);
+			if (err?.statusCode >= 400 && err?.statusCode < 500) {
+				removeIndexes.push(index)
+			}
+		}
+	}
+	if (removeIndexes.length) {
+		console.log(`Removing indexes ${removeIndexes} from subscriptions`)
+		removeIndexes.reverse();
+		for (const index of removeIndexes) {
+			subscriptions.splice(index, 1);
+		}
+		await writeFile(
+			"push-subscriptions.json",
+			JSON.stringify(subscriptions, undefined, "\t"),
+			"utf-8"
+		);
+	}
+	console.log("Push notices sent");
+}