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Chukwuma Anyadike
Chukwuma Anyadike

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Build a Simple Node.js Server with Full CRUD Capability

I wanted to create a prototypical todo application for some reason. The main reason that I wanted to do this was so that I could learn to create a server using node.js. Basically I wanted to create a backend with JavaScript. It was surprisingly simple. Let's do a quick walkthrough.

The Set Up

1) Create a Directory

mkdir todos-server
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2) Create the server file in todos-server folder (in this case I call it index.js)

touch index.js
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3) Initialize NPM

npm init -y
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This creates a package.json file with the following content

{
  "name": "todos-server",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "description": ""
}

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4) Install Express

npm install express
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After installing Express, go to the package.json file and include “type”: “module”. This allows ES6 module syntax (import/export) instead of the default common.js syntax (require).

Add Server Code in index.js file and start server.

1) Write server code in index.js file.

import express from 'express'; //allows http requests
import bodyParser from 'body-parser';  //allows us to take in an incoming request body
import todoRoutes from './routes/todos.js' //see todos.js file below

const app = express();
const PORT = 5000 //this is the port we will be listening on

app.use(bodyParser.json());
app.use('/todos', todoRoutes); //specify the path and router handler

app.get('/', (req, res) => {
    res.send('HELLO FROM HOMEPAGE');
})

app.listen(PORT, () => console.log(`Server running on port: http://localhost:${PORT}`));
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2) Start the server

node index.js
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3) Install Nodemon (This is optional). It is nice because it allows you to make changes without having to manually refresh the server.

npm install nodemon
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In the package.json file under "scripts" add this line

"start": "nodemon index.js"
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Now you can start your server using this command

npm start
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Create router folder, add routing file called todos.js with routes and CRUD functions

import express from 'express';
import { v4 as uuidv4 } from 'uuid';

const router = express.Router();

// Mock database
let todos = [];

// Getting the list of todos from the mock database
router.get('/', (req, res) => {
    res.send(todos);
})

// Getting a todo from the mock database
router.get('/:id', (req, res) => {
    const id = req.params.id;
    const todo = todos.find(todo => todo.id === id);
    if (todo)
        res.send(todo);
    else res.send('Todo not found');
})

// Adding a new todo to our mock database
router.post('/', (req, res) => {
    const todo = req.body;
    todos.push({ ...todo, id: uuidv4() });
    res.send(`${todo.task} has been added to the Database`);
})

// Changing an existing todo in our mock database
router.put('/:id', (req, res) => {
    const id = req.params.id;
    const updatedTodo = req.body;
    todos = todos.map(todo => todo.id === id ? updatedTodo : todo);
    res.send(`${id} has been changed in the Database`);
})

// Deleting a todo from our mock database
router.delete('/:id', (req, res) => {
    const id = req.params.id;
    todos = todos.filter(todo => todo.id !== id)
    res.send(`${id} deleted successfully`);
})

export default router
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HTTP Requests (CRUD Functions)

  • router.get()
  • router.post()
  • router.put() or router.patch()
  • router.delete()

These HTTP requests take two arguments.
1) A path
2) A callback function with req and res as arguments

With req and res we can take advantage of requests and responses.

  • req.body allows us to retrieve information to add to or edit our database.
  • req.params.id allows retrieval of the id value of our route.
  • res.send() allows our server to send a response.

Of note, import { v4 as uuidv4 } from 'uuid' allows us to generate unique ids for each todo.

Now that the server and routing files are complete I strongly encourage you to test these HTTP requests in the browser and/or with Postman. Overall, I found that it was easy to create a backend this way. The major pitfall is that none of that data is persisted to an actual database (SQL or noSQL). However, it can be used to provide data for a front end application. Now all I have to do is write the front end appplication. That's all folks.

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