如何使用聚合连接Deno和MongoDB的两个表？

deno cache --reload https://deno.land/x/mongo@v0.22.0/mod.ts
deno cache --reload https://deno.land/x/oak@v10.5.1/mod.ts

import { Application, Router } from "https://deno.land/x/oak@v10.5.1/mod.ts";
import { MongoClient } from "https://deno.land/x/mongo@v0.22.0/mod.ts";

const client = new MongoClient();
const url = "mongodb://localhost:27017";
const dbName = "test_db";

client.connect(url).then(async (conn) => {
  const db = conn.database(dbName);

  const router = new Router();
  router.get("/join", async (context) => {
    try {
      const collection1 = db.collection("collection1");
      const collection2 = db.collection("collection2");

      const result = await collection1.aggregate([
        {
          $lookup: {
            from: "collection2",
            localField: "collection2_id",
            foreignField: "_id",
            as: "joinedData"
          }
        }
      ]).toArray();

      context.response.body = result;
    } catch (error) {
      context.response.status = 500;
      context.response.body = { error: error.message };
    }
  });

  const app = new Application();
  app.use(router.routes());
  app.use(router.allowedMethods());

  console.log("Server running on http://localhost:8000");
  await app.listen({ port: 8000 });
}).catch(console.error);

deno run --allow-net --allow-read --allow-write app.ts