More TypeScript :)

frontend/server/api/champion/[alias].ts

@@ -1,15 +1,16 @@
+import { MongoClient } from 'mongodb';
 import {connectToDatabase, fetchLatestPatch} from '../../utils/mongo'
 
-async function championInfos(client, patch, championAlias) {
+async function championInfos(client: MongoClient, patch: string, championAlias: string) {
     const database = client.db("champions");
     const collection = database.collection(patch);
     const query = { alias:championAlias };
-    const championInfo = await collection.findOne(query);
+    const championInfo = (await collection.findOne(query)) as unknown as ChampionData;
     return championInfo
 }
 
 export default defineEventHandler(async (event) => {
-    const championAlias = getRouterParam(event, "alias").toLowerCase()
+    const championAlias = (getRouterParam(event, "alias") as string).toLowerCase()
     const client = await connectToDatabase();
     const latestPatch = await fetchLatestPatch(client);
     const data = await championInfos(client, latestPatch, championAlias);