Middleware is called every time a route is accessed.

const express = require('express')
const app = express()
const projectRouter = require('./routes/projects')

const { users } = require('./data')

// MIDDLEWARE
app.use(express.json())
app.use(setUser)
app.use('/projects', projectRouter)

app.get('/', (req, res) => {
  const whiz = req.foo || 'not set'
  res.send(`Home page: ${whiz}`)
})

app.get('dashboard', (req, res) => {
  res.send('Dashboard page')
})

app.get('/admin', (req, res) => {
  res.send('Admin page')
})

function foo(req, res, next) {
  req.foo = 'ding'
  
  next()
}

function setUser(req, res, next) {
  const userId = req.body.userId
  
  if (userId) {
    req.user = users.find(user => user.id === userId)
  }
  
  next()
}


// START SERVER
// todo: put in server.js

const PORT = process.env.PORT || 3000

app.listen(PORT, () => {
  console.log(`=== server started on port: ${PORT} ===`)
})