---
categories:
  - Programming Languages
tags: [backend, node-js, REST, APIs]
---

# Full example

```js
const express = require('express');
const app = express(); // convention to name Express as the app
const port = process.env.PORT || 3000;
const Joi = require('joi');
const helmet = require('helmet');
const morgan = require('morgan');
const courses = require('./routes/courses');

// Routes
app.use('/api/courses', courses);

// Middlewear
app.use(express.json());
app.use(helmet());

const courses = [
  {
    id: 1,
    name: 'First course',
  },
  {
    id: 2,
    name: 'Second course',
  },
  {
    id: 3,
    name: 'Third course',
  },
];

if (app.get('env') === 'development') {
  app.use(morgan('common'));
}

app.listen(port, () => console.log(`Listening on ${port}`));

function validateCourse(course) {
  const schema = Joi.object({
    name: Joi.string().min(3).required(),
  });

  const {error} = schema.validate(course);
  return error;
}

// Return all data from API
courses.get('/', (req, res) => {
  res.send(courses);
});

// Return a specific value
courses.get('/:id', (req, res) => {
  const course = courses.find((c) => c.id === parseInt(req.params.id));
  if (!course) res.status(404).send('A course with the given ID was not found');
  res.send(course);
});

// Add a new course
courses.post('/', (req, res) => {
  const schema = Joi.object({
    name: Joi.string().min(3).required(),
  });

  const {error} = schema.validate(req.body);
  if (error) return error.details.map((joiErr) => res.status(400).send(joiErr.message));

  const course = {
    id: courses.length + 1,
    name: req?.body.name,
  };
  courses.push(course);
  res.send(course);
});

// Update a course
courses.put('/:id', (req, res) => {
  const course = courses.find((c) => c.id === parseInt(req.params.id));

  if (!course) return res.status(404).send('A course with the given ID was not found');
  const {error} = validateCourse(req.body);

  if (error) return error.details.map((joiErr) => res.status(400).send(joiErr.message));

  course.name = req.body.name;
  res.send(course);
});

// Delete a course
courses.delete('/:id', (req, res) => {
  const course = courses.find((c) => c.id === parseInt(req.params.id));
  if (!course) return res.status(404).send('A course with the given ID was not found');

  courses.indexOf(course);
  courses.splice(index, 1);

  res.send(course);
});
```