Connect and use MongoDB with ES6 in Node 4

database.js

'use strict'

const MongoClient = require('mongodb')

class Database {

  constructor (uri) {
    this.uri = uri
    this.db = {}
    return this
  }

  connect () {
    return new Promise((resolve, reject) => {
      MongoClient.connect(this.uri, (err, db) => {
        if (err) reject(err)
        this.db = db
        resolve(this)
      })
    })
  }

  addReport (domain) {
    return new Promise((resolve, reject) => {
      this.db.collection('domains').findAndModify(
        { domain: domain }
      , {}
      , { $inc: { reported: 1 } }
      , { new: true, upsert: true }
      , (err, data) => {
          if (err) reject(err)
          resolve(data)
        })
    })

  }

  findReport (domain) {
    return new Promise((resolve, reject) => {
      this.db.collection('domains').findOne(
        { domain: domain }
      , { _id: false, reported: true }
      , (err, data) => {
          if (err) reject(err)
          if (data) {
            resolve(data.reported)
          } else {
            resolve(0)
          }
        })
    })
  }
}

module.exports = Database

database.test.js

'use strict'

const Database = require('../database')
    , dbUrl = process.env.MONGODB_URI || 'mongodb://localhost:27017/test'
    , assert = require('assert')

describe('Database', () => {
  let database

  beforeEach((done) => {
    database = new Database(dbUrl)
    database.connect()
      .then(() => { done() })
      .catch((err) => { done(err) })
  })

  afterEach(() => {
    database.db.dropDatabase()
  })

  it('should add a domain to the database with one report', (done) => {
    database.addReport('google.com')
      .then((data) => {
        assert.equal(data.value.domain, 'google.com', 'domain not inserted')
        return database.findReport('google.com')
      })
      .then((data) => {
        assert.equal(data, 1, 'incorrect number of reports')
        done()
      })
      .catch((err) => {
        done(err)
      })
  })
})

This is great! Thank you.