Part 3

part3/example/index.js

@@ -0,0 +1,83 @@
+const express = require("express")
+const app = express()
+
+app.use(express.json())
+
+let notes = [
+  {
+    id: 1,
+    content: "HTML is easy",
+    important: true
+  },
+  {
+    id: 2,
+    content: "Browser can execute only JavaScript",
+    important: false
+  },
+  {
+    id: 3,
+    content: "GET and POST are the most important methods of HTTP protocol",
+    important: true
+  }
+]
+
+app.get('/', (req, res) => {
+  res.send('<h1>Hello World!</h1>')
+})
+
+app.get('/api/notes', (req, res) => {
+  res.json(notes)
+})
+
+app.get('/api/notes/:id', (request, response) => {
+  const id = parseInt(request.params.id) 
+  if (Number.isNaN(id)) {
+    response.status(402).send("Bad Request")
+    return
+  }
+  const note = notes.find(note => note.id === id)
+  if (!note) {
+    response.status(404).send("Not Found")
+    return
+  }
+  response.json(note)
+})
+
+app.delete('/api/notes/:id', (request, response) => {
+  const id = Number(request.params.id)
+  notes = notes.filter(note => note.id !== id)
+
+  response.status(204).end()
+})
+
+const generateId = () => {
+  const maxId = notes.length > 0
+    ? Math.max(...notes.map(n => n.id))
+    : 0
+  return maxId + 1
+}
+
+app.post('/api/notes', (request, response) => {
+  const body = request.body
+
+  if (!body.content) {
+    return response.status(400).json({ 
+      error: 'content missing' 
+    })
+  }
+
+  const note = {
+    content: body.content,
+    important: body.important || false,
+    id: generateId(),
+  }
+
+  notes = notes.concat(note)
+
+  response.json(note)
+})
+
+const PORT = 3001
+app.listen(PORT, () => {
+  console.log(`Server running on port ${PORT}`)
+})