Refactoring yang akan kita lakukan meliputi:

• Menyederhanakan code yang digunakan untuk membuat koneksi ke MongoDB
• Memisahkan route & handler

Sharing Koneksi Database

Jika kita perhatikan pada code sebelumnya, proses koneksi ke MongoDB dilakukan di setiap handler. Hal ini membuat terjadi banyak duplicated code.

MongoDB driver sendiri sudah dilengkapi dengan mekanisme connection pooling, sehingga koneksi ke database hanya perlu dilakukan sekali.

Kita akan menggunakan object app.locals dari Express.js untuk menyimpan object collection.

Object app.locals memiliki properties yang bersifat local untuk aplikasi. Kita bisa anggap object ini seperti global object yang valuenya bisa diakses dimanapun selama masih di dalam aplikasi Express.js.

Step by Step

1. Tambahkan code berikut sebelum route

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1// Connect to Database
2
3MongoClient.connect(url, (err, client) => {
4  const db = client.db(dbName);
5  const notesCollection = db.collection('notes');
6
7  app.locals.notesCollection = notesCollection;
8});

2. Update semua routes

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1const express = require('express');
2const { MongoClient, ObjectId } = require('mongodb');
3const bodyParser = require('body-parser');
4
5const app = express();
6const port = 3001;
7
8// Connection URL
9const url = 'mongodb://localhost:27017';
10// Database Name
11const dbName = 'dinotesDB';
12
13app.use(bodyParser.urlencoded({ extended: true }));
14
15// Connect to Database
16
17MongoClient.connect(url, (err, client) => {
18  const db = client.db(dbName);
19  const notesCollection = db.collection('notes');
20
21  app.locals.notesCollection = notesCollection;
22});
23
24// Routes
25
26app.post('/note', (req, res) => {
27  const { notesCollection } = req.app.locals;
28  // Insert data to collection
29  notesCollection.insertOne(req.body).then((result) => {
30    console.log(result);
31  });
32
33  res.status(200).json('Data successfully saved');
34});
35
36app.get('/notes', (req, res) => {
37  const { notesCollection } = req.app.locals;
38
39  // find All Notes
40  notesCollection
41    .find()
42    .toArray()
43    .then((result) => {
44      res.status(200).json(result);
45    });
46});
47
48app.get('/note/:id', (req, res) => {
49  const { notesCollection } = req.app.locals;
50
51  // find Notes based on id
52  notesCollection.findOne({ _id: ObjectId(req.params.id) }).then((result) => {
53    res.status(200).json(result);
54  });
55});
56
57app.put('/note/:id', (req, res) => {
58  const { notesCollection } = req.app.locals;
59  // update data collection
60  notesCollection
61    .updateOne({ _id: ObjectId(req.params.id) }, { $set: { title: req.body.title, note: req.body.note } })
62    .then((result) => {
63      console.log(result);
64    });
65
66  res.status(200).json('Data successfully updated');
67});
68
69app.delete('/note/:id', (req, res) => {
70  const { notesCollection } = req.app.locals;
71
72  // delete data collection
73  notesCollection.deleteOne({ _id: ObjectId(req.params.id) }).then((result) => {
74    console.log(result);
75  });
76
77  res.status(200).json('Data successfully deleted');
78});
79
80app.listen(port, () => {
81  console.log(`Server listening at http://localhost:${port}`);
82});

Memutus Koneksi ke MongoDB

Kita tidak perlu mengatur (menyambungkan/memutus) koneksi ke MongoDB secara manual, hal ini sudah ditangani oleh MongoDB driver.

Jadi memutus koneksi ke MongoDB bisa dibilang tidak perlu dilakukan. Tapi jika kamu tetap ingin melakukannya kamu bisa update code server.js menjadi:

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1...
2
3// jadikan variable db menjadi global variable
4
5let db;
6
7MongoClient.connect(url, (err, client) => {
8  db = client.db(dbName);
9  const notesCollection = db.collection('notes');
10
11  app.locals.notesCollection = notesCollection;
12});
13
14...
15
16// tambahkan code berikut ini pada baris akhir server.js
17
18process.on('SIGINT', () => {
19  db.close();
20  process.exit();
21});

Memisahkan Route & Handler

Untuk memudahkan kita mengelola route, kita jadikan route yang ada menjadi sebuah module dengan cara memindahkannya dari api/server.js ke file terpisah.

Step by step

1. Buat sebuah file baru bernama route.js di dalam folder api

Struktur folder:

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1dinotes-app 
2    |--api 
3    |--routes.js 
4    |--server.js 
5    |--node_modules 
6    |--public 
7    |--src

Kita akan tambahkan express.Router, route handler yang digunakan untuk mengatur route di sebuah aplikasi Express.js.

2. Pindahkan semua route ke dari api/server.js ke api/routes.js kemudian ganti app dengan router:

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1const express = require('express');
2const { ObjectId } = require('mongodb');
3
4const router = express.Router();
5
6router.post('/note', (req, res) => {
7  const { notesCollection } = req.app.locals;
8  // Insert data to collection
9  notesCollection.insertOne(req.body).then((result) => {
10    console.log(result);
11  });
12
13  res.status(200).json('Data successfully saved');
14});
15
16router.get('/notes', (req, res) => {
17  const { notesCollection } = req.app.locals;
18
19  // find All Notes
20  notesCollection
21    .find()
22    .toArray()
23    .then((result) => {
24      res.status(200).json(result);
25    });
26});
27
28router.get('/note/:id', (req, res) => {
29  const { notesCollection } = req.app.locals;
30
31  // find Notes based on id
32  notesCollection.findOne({ _id: ObjectId(req.params.id) }).then((result) => {
33    res.status(200).json(result);
34  });
35});
36
37router.put('/note/:id', (req, res) => {
38  const { notesCollection } = req.app.locals;
39  // update data collection
40  notesCollection
41    .updateOne({ _id: ObjectId(req.params.id) }, { $set: { title: req.body.title, note: req.body.note } })
42    .then((result) => {
43      console.log(result);
44    });
45
46  res.status(200).json('Data successfully updated');
47});
48
49router.delete('/note/:id', (req, res) => {
50  const { notesCollection } = req.app.locals;
51
52  // delete data collection
53  notesCollection.deleteOne({ _id: ObjectId(req.params.id) }).then((result) => {
54    console.log(result);
55  });
56
57  res.status(200).json('Data successfully deleted');
58});
59
60module.exports = router;

3. Import module routes ke file server.js

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1const express = require('express');
2const { MongoClient } = require('mongodb');
3const bodyParser = require('body-parser');
4
5const routes = require('./routes');
6
7const app = express();
8const port = 3001;
9
10// Connection URL
11const url = 'mongodb://localhost:27017';
12// Database Name
13const dbName = 'dinotesDB';
14
15app.use(bodyParser.urlencoded({ extended: true }));
16
17// Connect to Database
18
19MongoClient.connect(url, (err, client) => {
20  const db = client.db(dbName);
21  const notesCollection = db.collection('notes');
22
23  app.locals.notesCollection = notesCollection;
24});
25
26// Routes
27
28app.use('/', routes);
29
30app.listen(port, () => {
31  console.log(`Server listening at http://localhost:${port}`);
32});

Sekarang kita pindahkan semua route handler ke file api/handler.js.

4. Buat sebuah file bernama handler.js di dalam folder api.

5. Kemudian pindahkan semua route handler ke file api/handler.js

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1/* eslint-disable no-console */
2const { ObjectId } = require('mongodb');
3
4exports.addNote = (req, res) => {
5  const { notesCollection } = req.app.locals;
6  // Insert data to collection
7  notesCollection.insertOne(req.body).then((result) => {
8    console.log(result);
9  });
10
11  res.status(200).json('Data successfully saved');
12};
13
14exports.getAllNotes = (req, res) => {
15  const { notesCollection } = req.app.locals;
16
17  // find All Notes
18  notesCollection
19    .find()
20    .toArray()
21    .then((result) => {
22      res.status(200).json(result);
23    });
24};
25
26exports.getNote = (req, res) => {
27  const { notesCollection } = req.app.locals;
28
29  // find Notes based on id
30  notesCollection.findOne({ _id: ObjectId(req.params.id) }).then((result) => {
31    res.status(200).json(result);
32  });
33};
34
35exports.updateNote = (req, res) => {
36  const { notesCollection } = req.app.locals;
37  // update data collection
38  notesCollection
39    .updateOne({ _id: ObjectId(req.params.id) }, { $set: { title: req.body.title, note: req.body.note } })
40    .then((result) => {
41      console.log(result);
42    });
43
44  res.status(200).json('Data successfully updated');
45};
46
47exports.deleteNote = (req, res) => {
48  const { notesCollection } = req.app.locals;
49
50  // delete data collection
51  notesCollection.deleteOne({ _id: ObjectId(req.params.id) }).then((result) => {
52    console.log(result);
53  });
54
55  res.status(200).json('Data successfully deleted');
56};

6. Update api/routes.js:

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1const express = require('express');
2
3const router = express.Router();
4
5const { addNote, getAllNotes, getNote, updateNote, deleteNote } = require('./handler');
6
7router.post('/note', addNote);
8router.get('/notes', getAllNotes);
9router.get('/note/:id', getNote);
10router.put('/note/:id', updateNote);
11router.delete('/note/:id', deleteNote);
12
13module.exports = router;

Sekarang kita memiliki tiga file yang memiliki tugasnya masing-masing:

• handler.js, mengatur semua route handler
• routes.js, mengatur semua route
• server.js, file utama dari server yang bertugas untuk load middleware, module, mengatur koneksi ke database dan menjalankan http server