Express.js Setup and Server Creation

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary purpose of the POST request in the context of routes?

To update existing resources

To create new data or resources (correct)

To delete resources from the server

To retrieve existing data from the server

How can you access a dynamic route parameter in an Express route handler?

Using req.body.id

Using req.params.id (correct)

Using req.route.id

Using req.query.id

What is a consequence of placing static routes below dynamic routes in Express?

Dynamic routes may never match

Static routes might not get called when they should (correct)

Static routes will not work at all

Static routes might override dynamic routes

What does the `router.route` method enable in Express?

It enables chaining multiple HTTP methods for a single route Signup and view all the answers

Which middleware is required to handle form data submitted to a route?

express.urlencoded Signup and view all the answers

What is the role of the `next` function in a router.param middleware?

To call the next middleware function in the stack Signup and view all the answers

How should related routes be organized in an Express application?

Group routes into separate files for clarity Signup and view all the answers

What method serves static files like HTML or CSS from a designated folder in Express?

express.static Signup and view all the answers

What command is used to install Express.js in a Node.js project?

npm i express Signup and view all the answers

Which script should be added to the package.json to utilize Nodemon for auto-restarting the server?

dev start: nodemon server.js Signup and view all the answers

How do you define a GET route in an Express.js application?

app.get(path, function(req, res)) Signup and view all the answers

What is the function of res.status(code).send(message) in Express.js?

To send a status code along with an optional message Signup and view all the answers

Which of the following is NOT a way to send a response from the server to the client in Express.js?

res.output() Signup and view all the answers

What configuration is needed to use EJS as the view engine in an Express.js application?

app.set('view engine', 'ejs') Signup and view all the answers

Which command is used to install the EJS view engine in a project?

npm install ejs Signup and view all the answers

How would you pass data from the server to an EJS view?

res.render(viewPath, { data: 'value' }) Signup and view all the answers

Study Notes

Setting up Express.js

Node.js is required for Express.js.
npm init -y creates a package.json file for dependency management.
Install Express.js using npm i express. Versions 4 and 5 are supported.
Install Nodemon as a development dependency: npm i --save-dev nodemon.
Create a dev start script in package.json to run nodemon server.js. This restarts the server when code changes.

Creating a Server

Create a server.js file for server logic.
Import Express: const express = require('express');
Initialize the Express app: const app = express();
Start the server: app.listen(3000);

Setting up Routes

app.get(path, function(req, res)) defines a GET route.
path specifies the URL (e.g., /).
req is the incoming request, res is the response.
Send a message with res.send("message").
res.sendStatus(statusCode) sends a status code (e.g., 500 for errors)

Express.js Response

res.status(code).send(message) sends a status code and message.
res.json(data) sends JSON data.
res.download(filePath) sends a file for download.
res.render(viewPath) renders an HTML file.

Creating Views

Express looks for views in the views folder.
ejs are used to generate HTML content.
Install ejs: npm install ejs.
Configure ejs: app.set('view engine', 'ejs').
.ejs files are used instead of .html.
Use <% %> for server-side code, and <%= %> for output.

Passing Data to Views

res.render(viewPath, { data: 'value' }) passes data to the view.
Access data in the view using locals: <%= locals.data %>.

Express Routers

Import Express: const express = require('express');
Create a router: const router = express.Router();
router.get(), router.post(), etc. define routes inside the router.
app.use('/path', router) mounts the router to a path.

Dynamic Routes

router.get('/users/:id', ...) defines a route with dynamic parameter id.
Access the parameter as req.params.id.

Clean Route Structure

Separate routes into files (e.g., users.js) for better organization.
Import these files into your main server file and use router instances.

Request Method Example: POST

router.post('/users', ...) handles POST requests to the /users route.
POST is used for creating resources.

Dynamic Parameters and Route Ordering

Routes are processed sequentially (top-to-bottom).
Dynamic routes (/user/:id) match any value after the placeholder.
Static routes (/new) should be placed above dynamic routes.

Route Chaining with `router.route`

router.route method chains methods (GET, PUT, DELETE) for a single path.
This improves route handling efficiency.

Middleware and `router.param`

Middleware runs between request and response.
router.param creates middleware for parameters.

Example of Middleware: Logging

Middleware can log request details.
app.use applies middleware to all routes.
Router-specific middleware applies only to associated routes.

Built-in Middleware

express.static serves static files.
express.urlencoded parses URL-encoded data from forms.
express.json parses JSON data from requests.

Example of Form Handling

Forms submit to /users route.
request.body contains form data (requires express.urlencoded).

Query Parameters

Access query parameters via request.query: e.g., request.query.name.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the essential steps for setting up an Express.js server, including project initialization with Node.js and defining routes. Test your knowledge on installing dependencies, using Nodemon, and starting your Express application. Perfect for beginners looking to enhance their web development skills.