An OOP example

index.js

'use strict'
const express = require('express')
const bodyParser = require('body-parser')
const todos = require('./todos')
require('./env')

const app = express()
app.use(bodyParser.json())
app.use(express.static('public'))

app.get('/todos', (req, res) => todos.retrieveAll(req, res))
app.post('/todos', (req, res) => todos.create(req, res))
app.put('/todos/:id', (req, res) => todos.update(req, res))
app.delete('/todos/:id', (req, res) => todos.delete(req, res))

const port = process.env.PORT || 9000
app.listen(port, () => console.log(`listening on ${port}`))

module.exports = app

todos.js

'use strict'
const Todos = require('./todos.storage')

exports.create = (req, res) => {
  if (!req.body || !req.body.text) return res.sendStatus(400)
  const text = req.body.text
  const todo = Todos.create(text)
  res.status(201).json(todo)
}

exports.retrieveAll = (req, res) => {
  const todos = Todos.retrieveAll()
  res.status(200).json(todos)
}

exports.update = (req, res) => {
  if (!req.params || !req.params.id || !req.body || !req.body.text) return res.sendStatus(400)
  const id = req.params.id
  const text = req.body.text
  const todo = Todos.update(id, text)
  res.status(200).json(todo)
}

exports.delete = (req, res) => {
  if (!req.params || !req.params.id) return res.sendStatus(400)
  const id = req.params.id
  const todo = Todos.delete(id)
  res.status(200).json(todo)
}

todos.storage.js

'use strict'
let Storage = function() {
  this.items = {}
  this.id = 0
}

Storage.prototype.create = function(text) {
  const id = this.id
  const item = { text, id }
  this.items = Object.assign({}, this.items, { [id]: item })
  this.id += 1
  return item
}

Storage.prototype.retrieveAll = function() {
  return this.items
}

Storage.prototype.update = function(id, text) {
  if (isNaN(id) || !text) return 'not valid'
  let item
  if (this.items[id]) {
    item = this.items[id]
    item.text = text
    this.items = Object.assign({}, this.items,
      Object.keys(this.items).reduce((result, key) => {
        if (key === id) { result[key] = item }
        return result
      }, {}))
  } else {
    item = this.create(text)
  }
  return item
}

Storage.prototype.delete = function(id) {
  if (isNaN(id)) return 'not valid'
  if (!this.items[id]) return 'not found'
  const item = this.items[id]
  this.items = Object.assign({},
    Object.keys(this.items).reduce((result, key) => {
      if (key !== id) { result[key] = this.items[key] }
      return result
    }, {}))
  return item
}

const Todos = new Storage()

module.exports = Todos

todos.test.js

const chai = require('chai')
const chaiHttp = require('chai-http')
const Todos = require('./todos.storage')
const app = require('./index')

const should = chai.should()

chai.use(chaiHttp)

describe('Todos', function() {
  it('should create a todo on post', function(done) {
    const text = 'Learning nodejs'
    chai.request(app)
      .post('/todos')
      .send({ text })
      .end(function(err, res) {
        res.should.have.status(201)
        res.should.be.json
        res.body.id.should.be.a('number')
        res.body.text.should.equal(text)
        done()
      })
  })
  it('should retrieve todos on get', function(done) {
    chai.request(app)
      .get('/todos')
      .end(function(err, res) {
        res.should.have.status(200)
        res.should.be.json
        res.body[0].id.should.be.a('number')
        res.body[0].text.should.a('string')
        done()
      })
  })
  it('should update a todo on put', function(done) {
    const text = 'Learning nodejs is fun'
    chai.request(app)
      .put('/todos/0')
      .send({ 'id': 0, text })
      .end(function(err, res) {
        res.should.have.status(200)
        res.should.be.json
        res.body.id.should.be.a('number')
        res.body.text.should.equal(text)
        done()
      })
  })
  it('should delete a todo on delete', function(done) {
    const text = 'Learning nodejs is fun'
    chai.request(app)
      .delete('/todos/0')
      .send({ 'id': 0 })
      .end(function(err, res) {
        res.should.have.status(200)
        res.should.be.json
        res.body.id.should.be.a('number')
        res.body.text.should.equal(text)
        done()
      })
  })
})