index.js

const express = require('express')
const app = express()
const bodyParser = require('body-parser')
const morgan = require('morgan')
const cors = require('cors')

app.use(bodyParser.json())
app.use(morgan(':method :url :status :res[content-length] - :response-time ms :body'))
morgan.token('body', function (req, res) { return JSON.stringify(req.body) })
app.use(express.static('build'))
app.use(cors())

let persons = [
  {
    id: 1,
    name: "Hendrik",
    number: "3546564323",
  },
  {
    id: 2,
    name: "Smith",
    number: "76543234567",
  },
  {
    id: 3,
    name: "George",
    number: "09876543452",
  }
]
app.get('/info', (req, res) => {
    res.send(`<p>Phonebook has info for ${persons.length} people</p> <p>${new Date}</p>`)

})

app.get('/api/persons', (req, res) => {
    res.json(persons)
})

app.get('/api/persons/:id', (request, response) => {
    const id = Number(request.params.id)
    const person = persons.find(person => person.id === id)

    if (person) {
	response.json(person)
    } else {
	response.status(404).end()
    }
})

const generateId = () => {
  return Math.floor(Math.random() * Math.floor(1000));
}

app.post('/api/persons', (request, response) => {
    const body = request.body
    console.log(body)
    if (!body.name) {
      return response.status(400).json({ 
        error: 'name missing' 
    })
  } else if (!body.number) {
      return response.status(400).json({
        error: 'number missing'
      })
  } else if (persons.map(p=>p.name).includes(body.name)) {
      return response.status(400).json({
        error: 'name must be unique'
      })
  }
 
  

    const person = {
      id: generateId(),
      name: body.name,
      number: body.number
    }
    persons = persons.concat(person)

    response.json(person)
})

app.delete('/api/persons/:id', (request, response) => {
    const id = Number(request.params.id)
    persons = persons.filter(person=> person.id !== id)

    response.status(204).end()
})


const PORT = process.env.PORT || 3001
app.listen(PORT, () => {
	console.log(`Server running on port ${PORT}`)
})