It is not clear what assert is. Which great god will answer it?

The following is an example of a connection to an official document

const MongoClient = require('mongodb').MongoClient;
 const assert = require('assert');
 
 // Connection URL
 const url = 'mongodb://localhost:27017';
 
 // Database Name
 const dbName = 'myproject';
 
 // Create a new MongoClient
 const client = new MongoClient(url);
 
 // Use connect method to connect to the Server
 client.connect(function(err) {
 assert.equal(null, err);
 console.log("Connected successfully to server");
 
 const db = client.db(dbName);
 
 client.close();
 });