index.js

const express = require('express')
const cors = require('cors')
const morgan = require('morgan')

const app = express()
app.use(cors())
app.use(express.json())

// register token
morgan.token('body', (req, res) => JSON.stringify(req.body))

app.use(
  morgan((tokens, req, res) => {
    return [
      tokens.method(req, res),
      tokens.url(req, res),
      tokens.status(req, res),
      tokens.res(req, res, 'content-length'), '-',
      tokens['response-time'](req, res), 'ms',
      tokens['body'](req, res),
    ].join(' ')
  })
)

let persons = [
  {
    "name": "Arto Hellas",
    "number": "040-123456",
    "id": 1
  },
  {
    "name": "Ada Lovelace",
    "number": "39-44-5323523",
    "id": 2
  },
  {
    "name": "Dan Abramov",
    "number": "12-43-234345",
    "id": 3
  },
  {
    "name": "Mary Poppendieck",
    "number": "39-23-6423122",
    "id": 4
  }
]


const randomMinMax = (min, max) => {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min + 1) + min);
}

const uniqueID = () => {
  let id = 0

  do {
    id = randomMinMax(1, Number.MAX_SAFE_INTEGER)

  } while ( persons.some(item => item.id == id) )

  return id
}


app.get("/info", (req, res) =>  {
  const count = `<p>Phonebook has info for ${persons.length} people</p>`
  const date = `<p>${new Date().toUTCString()}</p>`
  res.send(count + date)
})


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


app.get("/api/persons/:id", (req, res) => {
  const id = req.params.id
  const person = persons.find(p => p.id == id)

  if (person) {
    res.json(person)

  } else {
    res.status(404).end()
  }

})


app.delete("/api/persons/:id", (req, res) => {
  const id = req.params.id
  const index = persons.findIndex(p => p.id == id)

  if (index != -1) {
    persons.splice(index, 1)
    res.status(200).end()

  } else {
    res.status(404).end()
  }

})


app.post("/api/persons", (req, res) => {
  const obj = Object(req.body)
  const keys = Object.keys(obj)

  if (keys.length != 2) {
    res.status(400)
    res.json({ "error": "name or number is missing" })
    res.end()
    return
  }

  const name = obj[keys[0]]
  const number = obj[keys[1]]

  if (persons.some(item => item.name == name)) {
    res.status(400)
    res.json({ "error": "name must be unique" })
    res.end()
    return
  }

  const id = uniqueID()

  persons.push({name, number, id})

  res.status(200).end()
})



const PORT = 3001

app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`)
})