How to export mongodb db collections to another js file?

Question

I have initialized the connection to my mongodb and now export the db to other nodejs files. How can I do that?

i thought of something like this but it is giving errors.

let database;
export const connectDB = async () => {
  const client = new MongoClient(config.dbUri, {
    useUnifiedTopology: true,
  });

  try {
    await client.connect();
    database = client.db('azkaben');
    logger.info('Connected to Database');
  } catch (e) {
    logger.error(e);
  } finally {
    await client.close();
  }
};

export default database

Error : undefined value of database

Tushar Gupta - curioustushar · Accepted Answer · 2021-03-27 19:27:32Z

1

database will always be null when you import it.

connectDB is aync call by the time it executes your database variable is already loaded as null.

connectDB you can return database from here.

export const connectDB = async () => {
  const client = new MongoClient(config.dbUri, {
    useUnifiedTopology: true,
  });

  try {
    await client.connect();
    database = client.db('azkaben');
    return database; // you can get from here
    logger.info('Connected to Database');
  } catch (e) {
    logger.error(e);
  } finally {
    await client.close();
  }
};

Updated code

export const connectDB = async () => {
  if (database) return database; // return if database already connected. 
  const client = new MongoClient(config.dbUri, {
    useUnifiedTopology: true,
  });

  try {
    await client.connect();
    database = client.db('azkaben');
    return database; // you can get from here
    logger.info('Connected to Database');
  } catch (e) {
    logger.error(e);
  } finally {
    await client.close();
  }
};

edited Mar 27, 2021 at 19:27

answered Mar 27, 2021 at 19:13

Tushar Gupta - curioustushar

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4 Comments

anita shrivastava Over a year ago

But, if i will do that , I have to connect to database every time I import that db

Tushar Gupta - curioustushar Over a year ago

@anitashrivastava In that case you can use const getDatabse = async() => databse; function to get the value, but you need to make sure the application is connected to database 1st after that your code execution starts. getDatabse().then(db => query).

Tushar Gupta - curioustushar Over a year ago

@anitashrivastava or you can even use const getDatabse => databse; but sure your database is connected before you call getDatabse.

Tushar Gupta - curioustushar Over a year ago

@anitashrivastava updated answer with 1 more option.

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