(node:26027) UnhandledPromiseRejectionWarning: MongoError: a collection 'bad-node-mongodb-3-6-0.tester' already exists
    at MessageStream.messageHandler (.../bad-mongo/node_modules/mongodb/lib/cmap/connection.js:266:20)
    at MessageStream.emit (events.js:315:20)
    at processIncomingData (.../bad-mongo/node_modules/mongodb/lib/cmap/message_stream.js:144:12)
    at MessageStream._write (.../bad-mongo/node_modules/mongodb/lib/cmap/message_stream.js:42:5)
    at doWrite (_stream_writable.js:403:12)
    at writeOrBuffer (_stream_writable.js:387:5)
    at MessageStream.Writable.write (_stream_writable.js:318:11)
    at Socket.ondata (_stream_readable.js:717:22)
    at Socket.emit (events.js:315:20)
    at addChunk (_stream_readable.js:295:12)

const { MongoClient } = require("mongodb")
const database = "mongodb://localhost:27017/bad-node-mongodb-3-6-0"

async function startup() {    
const connection = await MongoClient.connect(database, { useUnifiedTopology: true })

    const db = connection.db()

    await db.createCollection("tester")

    console.log("all done")
}

startup()

{ "name": "bad-mongo", "version": "1.0.0", "main": "index.js", "license": "MIT", "scripts": { "start": "node index.js" }, "dependencies": { "mongodb": "^3.6.0" }}