Using the Node.js driver for CouchDB (Installation and Usage)

1. Install Node.js

First, you need to install Node.js, supporting version 14 or above. You can find the installer on the Node.js Official Website.

2. Install CouchDB's Node.js Driver

Use the npm command to install CouchDB's Node.js driver:

npm install couchdb

If you need to install other dependencies at the same time, you can add the following options:

npm install --save-dev couchdb@latest couchdb-include

3. Configure CouchDB

Open the config.json file and set the following content:

{
  "url": "http://localhost:5984",
  "username": "",
  "password": ""
}

Replace http://localhost:5984 with the actual CouchDB URL, and fill in your username and password in the blank spaces.

4. Create a New Database

Use the following command to create a new database:

const couchdb = require('couchdb');

const db = new couchdb('mydatabase');

Replace mydatabase with the name of the database you want to create.

5. Start CouchDB

Start CouchDB. Depending on the specific operating system and environment, the start command may vary. It is usually started using the following command:

nodemon index.js

6. Access the Database

Use the following command to access the database:

const db = new couchdb('mydatabase');

// Read data
db.getDoc('mydocument', (err, doc) => {
  if (err) console.error(err);
  else console.log(doc);
});

// Switch database
const anotherDb = new couchdb('anotherdatabase');

7. Error Handling

In practical applications, error situations need to be considered, such as connection failures, authorization exceptions, etc. You can use the following code for error handling:

try {
  // Read data
} catch (err) {
  console.error(err);
}

// Similarly applicable for writing data and switching database operations

8. Examples

The following is a simple example showing how to use CouchDB's Node.js driver to create a new database and read data:

const couchdb = require('couchdb');

// Key values: database name, username, and password
const dbOptions = {
  url: 'http://localhost:5984',
  username: '',
  password: ''
};

const db = new couchdb(dbOptions);

const myDatabase = new couchdb(dbOptions);
myDatabase.createDatabase('mydatabase', (err) => {
  if (err) console.error(err);
  else console.log('Database created successfully');
});

// Read data
const doc = myDatabase.getDoc('mydocument');
if (!doc) {
  // If it does not exist, create a new document
  const newDoc = { foo: 'bar' };
  myDatabase.createDocument('mydocument', newDoc, (err) => {
    if (err) console.error(err);
    else console.log(newDoc);
  });
} else {
  console.log(doc.value.foo); // Output: bar
}

9. Conclusion

This article introduces how to use the Node.js driver to implement basic operations of CouchDB in JavaScript, such as creating databases, reading data, writing data, and switching databases. It should be noted that in practical applications, error situations should be handled, and security measures should be considered.