MongoDB Container Connection Hangs with no Response

This is my first time trying MongoDB. I'm just trying to simply connect to it successfully. I'm following the W3 tutorial here: https://www.w3schools.com/nodejs/nodejs_mongodb.asp docker-compose.yml

version: '3.1'
services:
  mongo:
    image: mongo
    restart: unless-stopped
    ports:
      - 27017:27017
    volumes:
      - /home/username/mongodb/data:/data/db
  mongo-express:
    image: mongo-express
    restart: unless-stopped
    ports:
      - 8089:8081

With that, the mongo-express UI seems to work fine. I can create a database etc... but, this does not work: create_db_test.js

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mytestdb";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  console.log("Database created!");
  db.close();
});

and

node create_db_test.js

and this just hangs. There's just a blank line on the command line and it does nothing. The database is not created. The output from the container looks like this:

mongodb-mongo-1          | {"t":{"$date":"2023-05-27T16:04:20.449+00:00"},"s":"I",  "c":"NETWORK",  "id":22943,   "ctx":"listener","msg":"Connection accepted","attr":{"remote":"172.18.0.1:39946","uuid":"abbbc8ad-fceb-4a6b-b6e4-12d123a837b7","connectionId":2,"connectionCount":2}}
mongodb-mongo-1          | {"t":{"$date":"2023-05-27T16:04:20.469+00:00"},"s":"I",  "c":"NETWORK",  "id":51800,   "ctx":"conn2","msg":"client metadata","attr":{"remote":"172.18.0.1:39946","client":"conn2","doc":{"driver":{"name":"nodejs","version":"5.5.0"},"platform":"Node.js v18.12.1, LE","os":{"name":"linux","architecture":"arm64","version":"6.1.25-37.47.amzn2023.aarch64","type":"Linux"}}}}
mongodb-mongo-1          | {"t":{"$date":"2023-05-27T16:04:30.983+00:00"},"s":"I",  "c":"NETWORK",  "id":22943,   "ctx":"listener","msg":"Connection accepted","attr":{"remote":"172.18.0.1:60246","uuid":"47895fe4-78f3-4401-a886-4d5ef832c66b","connectionId":3,"connectionCount":3}}
mongodb-mongo-1          | {"t":{"$date":"2023-05-27T16:04:30.985+00:00"},"s":"I",  "c":"NETWORK",  "id":51800,   "ctx":"conn3","msg":"client metadata","attr":{"remote":"172.18.0.1:60246","client":"conn3","doc":{"driver":{"name":"nodejs","version":"5.5.0"},"platform":"Node.js v18.12.1, LE","os":{"name":"linux","architecture":"arm64","version":"6.1.25-37.47.amzn2023.aarch64","type":"Linux"}}}}

When I interrupt create_db_test.js with Ctrl-C, the container log suggests that the connection has been open the whole time and is now ended:

mongodb-mongo-1          | {"t":{"$date":"2023-05-27T16:05:10.053+00:00"},"s":"I",  "c":"NETWORK",  "id":22944,   "ctx":"conn3","msg":"Connection ended","attr":{"remote":"172.18.0.1:60246","uuid":"47895fe4-78f3-4401-a886-4d5ef832c66b","connectionId":3,"connectionCount":2}}
mongodb-mongo-1          | {"t":{"$date":"2023-05-27T16:05:10.053+00:00"},"s":"I",  "c":"-",        "id":20883,   "ctx":"conn2","msg":"Interrupted operation as its client disconnected","attr":{"opId":620}}
mongodb-mongo-1          | {"t":{"$date":"2023-05-27T16:05:10.054+00:00"},"s":"I",  "c":"NETWORK",  "id":22944,   "ctx":"conn2","msg":"Connection ended","attr":{"remote":"172.18.0.1:39946","uuid":"abbbc8ad-fceb-4a6b-b6e4-12d123a837b7","connectionId":2,"connectionCount":1}}

What am I missing here?