NodeJS/MongoDB: Only connect one time to DB

Question

I'm doing some e2e tests of a nodeJS application. In the before/after hooks I need to add/remove some mongoDB documents and this is how I do that:

Shouldn't it be possible to connect only one time to the mongo server at all?

What I would like to do:

Remove all documents { _id: articleId } at the beginning (right now missing in the code)
Insert new document to DB (collection.insertOne(articles.main))
Remove all documents after the tests has be finished

My code feels not very good to me

describe('article module', function () {
  before(function () {
    MongoClient.connect(mongoServer, (err, db) => {
      expect(err).to.be.null
      db.collection('content', (err, collection) => {
        expect(err).to.be.null
        collection.findOne({ _id: articleId }, (err, item) => {
          expect(err).to.be.null
          if (!item) collection.insertOne(articles.main)
          db.close()
        })
      })
    })
  })

  after(function () {
    MongoClient.connect(mongoServer, (err, db) => {
      expect(err).to.be.null
      db.collection('content', (err, collection) => {
        expect(err).to.be.null
        collection.remove({ _id: articleId }, (err, removed) => {
          expect(err).to.be.null
          db.close()
        })
      })
    })
  })
})

Just put it into a function and call that function........................... — Eric
– Eric, Commented Aug 14, 2017 at 20:14
You can actually chain this using promises, it'll make it cleaner — Avindu Hewa
– Avindu Hewa, Commented Aug 15, 2017 at 7:43
I don't really see what's wrong with what you have, I'd say it's cleaner to open a connection when needed as opposed to keeping an active connection opened for the full spec (unless connect yields a poolable connection). — James
– James, Commented Aug 15, 2017 at 10:20
@James Ok, thanks for that. I was thinking connecting once would be better... So I will keep everything. — user3142695
– user3142695, Commented Aug 15, 2017 at 10:23

Avindu Hewa · Accepted Answer · 2017-08-15 09:28:42Z

1

describe('article module', () => {
  before(() => {

    MongoClient.connect(mongoServer, (err, db) => {
      expect(err).to.be.null

      const content = db.collection('content');

      content.findOne({ _id: articleId })
      .then(item => {
        return content.insertOne(articles.main);
      })
      .then(insertResult => {
        db.close();
      })
      .catch(err => {
        expect(err).to.be.null;
      })
    })

  })

  after(() => {
    MongoClient.connect(mongoServer, (err, db) => {
      expect(err).to.be.null

      const content = db.collection('content');

      content.remove({ _id: articleId })
      .then(removed => {
        db.close();
      })
      .catch(err => {
        expect(err).to.be.null;
      })
    })
  })
})

You can call the db using a third party promise as well

answered Aug 15, 2017 at 9:28

Avindu Hewa

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1 Comment

Avindu Hewa Over a year ago

I hope it helped , but i dont understand the downvote

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