server.js

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

const app = express();

app.use(bodyParser.json());
app.use(cors());

// Rough code to let us store notes in memory with out any DB complexity
const notes = {
  1: {
    id: 1,
    title: 'Test Note',
    body: 'This is a test note object that will be available by default',
    created_at: Date.now(),
    created_by: 'admin',
    edit_history: [{
      edited_at: Date.now(),
      edited_by: 'A User',
    }],
  },
};

// Generates the next id from the global notes list.
const createNextId = () => Number.parseInt(Math.max(...Object.keys(notes).map((key) => Number.parseInt(key))), 10) + 1;

const addNote = ({ title, body, created_by }) => {
  const id = createNextId();
  notes[id] = {
    id,
    title,
    body,
    created_by,
    created_at: Date.now(),
    edit_history: [],
  };
  return notes[id];
};

const getNotes = () => notes;

const getNote = (id) => {
  const note = getNotes()[id];
  return note || null;
};

const updateNote = (id, update = {}) => {
  const note = getNote(id);

  const { title, body } = update;
  Object.assign(note, { title, body });

  if (update.edited_by) {
    note.edit_history.push({
      edited_by: update.edited_by,
      edited_at: Date.now(),
    });
  }
  return note;
};

const removeNote = (id) => {
  if (getNote(id)) {
    delete getNotes()[id];
    return true;
  }
  return false;
};

app.post('/notes', (req, res) => {
  const note = addNote(req.body);
  res.json(note);
});

app.get('/notes', (req, res) => {
  res.json(Object.values(getNotes()));
});

app.get('/notes/:id', (req, res) => {
  const note = getNote(req.params.id);
  res.json(note);
});

app.post('/notes/:id', (req, res) => {
  const note = updateNote(req.params.id, req.body);
  res.json(note);
});

app.delete('/notes/:id', (req, res) => {
  const result = removeNote(req.params.id);
  res.json(result);
});

app.listen(5000, () => console.log('Server running on port 5000'));