const { MongoClient } = require('./lib/node_modules/mongodb');

const main = async () => {
    const url = '...';

    const client = new MongoClient(url, { useUnifiedTopology: true });
    await client.connect();

    const db = client.db('testdb');
    const demo = db.collection('demo');

    console.log('count', await demo.countDocuments({}));
    // > count 81

    await client.close();

    await client.connect();
    // > the options [servers] is not supported
    // > the options [caseTranslate] is not supported
    // > the options [dbName] is not supported
    // > the options [credentials] is not supported

    console.log('count', await demo.countDocuments({}));
    // > MongoError: Topology is closed, please connect
    // >     at processWaitQueue (node_modules/mongodb/lib/core/sdam/topology.js:998:42)
    // >     at NativeTopology.selectServer (node_modules/mongodb/lib/core/sdam/topology.js:440:5)
    // >     at executeWithServerSelection (node_modules/mongodb/lib/operations/execute_operation.js:137:12)
    // >     at executeOperation (node_modules/mongodb/lib/operations/execute_operation.js:75:7)
    // >     at Collection.countDocuments (node_modules/mongodb/lib/collection.js:1569:10)
    // >     at main (test.js:23:37)
    // >     at processTicksAndRejections (internal/process/task_queues.js:93:5) {
    // >   name: 'MongoError',
    // >   [Symbol(mongoErrorContextSymbol)]: {}
    // > }    await client.close();
}
main().catch(console.error);