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Project Notes

Day 1

  • Initialized Node.js project
  • Set up Git and GitHub connection
  • Learned about npm init

What I Learned

  • Git init creates a local repository
  • Need Personal Access Token for GitHub authentication
  • .gitignore prevents node_modules from being pushed

Express server

Install Express

Concept:

  • Express is a minimal web framework for Node.js
  • Installing it adds Express to your node_modules folder and records it in package.json under dependencies
  • The -save flag is now default in modern npm, so npm install express is sufficient
  • use code in terminal
npm install express

N/B

  • "type": "module", // since i want to use "import express from "express" " -- i added this for the ES Modules

  • so my package.json file looks like this

{
  "name": "api2",
  "version": "1.0.0",
  "type": "module",  
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^5.1.0"
  }
}
  • Instead of this
{
  "name": "api2",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^5.1.0"
  }
}

A: ES Modules

Import Express:

const express = require("express")
// or import express from "express"
  • Loads the Express library
  • Returns a function that creates Express applications

B: CommonJS (Traditional)

express = require("express")

// CommonJS

Create Application Instance:

const app = express()
  • Calls the Express function to create your app
  • This app object has methods for routing, middleware, and configuration

3. Define the Port:

const PORT = 3000
  • Specifies which port your server listens on
  • Common development ports: 3000, 8000, 8080
  • In production (like Render), you'll use process.env.PORT

4. Add Middleware:

app.use(express.json())
  • What is middleware? Functions that execute during the request-response cycle
  • express.json() parses incoming JSON payloads
  • Without this, req.body would be undefined for JSON requests

5. Define Routes:

app.get("/", (req, res) => {
    res.json({
	    firstName: "John",
	    lastName: "Doe"
    })
})
​
  • app.get() defines a route for GET requests
  • First parameter: the path ("/" is the root)
  • Second parameter: handler function with req (request) and res (response)
  • res.json() sends a JSON response

6. Start the Server:

app.listen(PORT, () => {
    console.log(`Server is running on http://localhost:${PORT}`)
})
​
  • Tells Express to listen for requests on the specified port
  • The callback runs once the server successfully starts

Running the server

We could run the server with the command

node server.js

but this i not very developer friendly, because for every change we would need to stop the server, restart it .. naaah, that’s too much !

so we can add a script in the package.json file

Concept:

  • Scripts in package.json let you define custom commands
  • Makes it easier for others (and yourself) to run the project

Edit your package.json and add:

"scripts": {
    "start": "node server.js",
    "dev": "nodemon server.js"
}

The dev script requires nodemon (install with npm install --save-dev nodemon) which auto-restarts on file changes.

So, install the package nodemon as a development dependency. This means, it won’t be installed when we deploy the application on Render or some other cloud service.

Run Your Server

npm run dev

You should see: Server is running on http://localhost:3000

Test Your Server

Open your browser and visit http://localhost:3000 or use a tool like:

  • Browser: Just type the URL
  • Postman: For testing POST/PUT/DELETE requests
  • curl: Command line tool
  • Thunder Client: VS Code extension

To exit the running section of the terminal

  • Use Ctrl + C

Little test

if you add this middleware on your application

// middleware to log request body
app.use(async (req, res, next) => {
	const date = new Date().toISOString()
	console.log(`[${date}] ${req.method} ${req.url}`)

	
	const response = await fetch("https://jsonplaceholder.typicode.com/users/1")
	const data = await response.json()
	req.data = data
	console.log(data)
	
	next()
})

and then add this function right after:

app.get("/", (req, res) => {
	const data = req.data
	res.json({ users, data })
})

you will be sending the hard-coded data from your application

const users = [
	{ id: 1, name: "Alice" },
	{ id: 2, name: "Bob" },
	{ id: 3, name: "Charlie" },
	{ id: 4, name: "Dave" },
]

PLUS

the data that you just brought using the fetch function ! In this case is:

{
	"id": 1,
	"name": "Leanne Graham",
	"username": "Bret",
	"email": "Sincere@april.biz",
	"address": {
		"street": "Kulas Light",
		"suite": "Apt. 556",
		"city": "Gwenborough",
		"zipcode": "92998-3874",
		"geo": {
				"lat": "-37.3159",
				"lng": "81.1496"
				}
		},
		"phone": "1-770-736-8031 x56442",
		"website": "hildegard.org",
		"company": {
			"name": "Romaguera-Crona",
			"catchPhrase": "Multi-layered client-server neural-net",
			"bs": "harness real-time e-markets"
			}
}