index.js

const express = require('express');
const app = express();
const cors = require('cors');

app.use(express.json());
app.use(cors());
app.use(express.static('build'));

let notes = [
	{
		id: 1,
		content: 'HTML is easy',
		date: '2022-05-30T17:30:31.098Z',
		important: true,
	},
	{
		id: 2,
		content: 'Browser can execute only Javascript',
		date: '2022-05-30T18:39:34.091Z',
		important: false,
	},
	{
		id: 3,
		content: 'GET and POST are the most important methods of HTTP protocol',
		date: '2022-05-30T19:20:14.298Z',
		important: true,
	},
];

app.get('/', (request, response) => {
	response.send('<h1>Hello World!</h1>');
});

app.get('/api/notes', (request, response) => {
	response.json(notes);
});

app.get('/api/notes/:id', (request, response) => {
	const id = Number(request.params.id);
	const note = notes.find((note) => note.id === id);
	if (note) {
		response.json(note);
	} else {
		response.status(404).end();
	}
});

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,
		date: new Date(),
		id: generateId(),
	};

	notes = notes.concat(note);
	response.json(note);
});

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