Project Description

• Summary: Practice Node.js with MongoDB; implements helper functions to perform basic CRUD operations (see MongoDB.js).

CRUD Functions (one-liners)

• createDBConnection: Create and return a new MongoClient for a given connection string and store it as the most-recent client.
• connectToDatabase: Ensure the provided client is connected and return the selected database object.
• insertData: Insert a single document into a collection, adding a createdAt timestamp.
• insertManyDocuments: Insert multiple documents into a collection, adding createdAt to each.
• getAllDataByCollection: Return all documents from a collection as an array.
• getDataById: Find and return a single document by _id, attempting to convert string ids to ObjectId when possible.
• deleteDataById: Delete a single document matching the provided query from a collection.
• deleteManyByQuery: Delete all documents matching a query from a collection.
• closeConnection: Close the stored MongoDB client connection if one exists.

Notes on MongoDB client functions used

• MongoClient / import: The code imports MongoClient and ObjectId from the mongodb package to create clients and handle _id conversions.
• new MongoClient(connectionString, options): Instantiates a client object without connecting yet.
• client.connect(): Establishes the network connection to MongoDB (the code treats this as idempotent and awaits it when present).
• client.db(dbName): Returns a Db instance scoped to dbName for collection operations.
• db.collection(name): Returns a collection handle used to perform CRUD operations.
• collection.insertOne(doc) / insertMany(docs): Insert operations for single and multiple documents respectively.
• collection.find(query).toArray(): Run a query cursor and materialize results as an array (used to get all documents).
• collection.findOne(query): Return a single document matching a query (used for getting by id).
• collection.deleteOne(query) / deleteMany(query): Remove single or multiple documents matching a query.
• client.close(): Close the active client connection and free resources.
• ObjectId(value): Convert a string to a MongoDB ObjectId (wrapped in try/catch in the code to allow non-ObjectId keys).

Usage (short)

const {
	createDBConnection,
	insertData,
	getAllDataByCollection,
	getDataById,
	deleteDataById,
	closeConnection,
} = require('./MongoDB');

(async () => {
	const client = createDBConnection('mongodb://localhost:27017');
	const db = 'testdb';
	const col = 'items';

	await insertData(client, db, col, { name: 'Example' });
	const all = await getAllDataByCollection(client, db, col);
	const one = await getDataById(client, db, col, all[0]._id);
	await deleteDataById(client, db, col, { _id: one._id });
	await closeConnection();
})();