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Express Boilerplate - Handling Errors In Your Express Application

Express Boilerplate is a pre-configured Node.js application framework that provides a starting point for building web applications. It includes essential packages and modules that are commonly used in web development.

Kelvin Farr
Jun 01, 20239410 Shares165080 Views
Express Boilerplateis a pre-configured Node.js application framework that provides a starting point for building web applications. It includes essential packages and modules that are commonly used in web development, such as:
  • Express.js- A popular web framework for Node.js that simplifies the process of building web applications.
  • Mongoose- An Object-Document Mapping (ODM) library for MongoDB that provides a higher level of abstraction than the MongoDB driver.
  • Passport- An authentication middleware that makes it easy to add user authentication to your application.
  • Winston - A logging library that provides a simple and consistent API for logging information, warnings, and errors.
  • Helmet- A collection of middleware functions that help secure Express applications by setting various HTTP headers.
Express Boilerplate is designed to help you get up and running quickly, so you can focus on building your application's business logic instead of setting up the same basic configuration every time.

Why Use Express Boilerplate?

Using a boilerplate can save you a significant amount of time and effort. Rather than starting each project from scratch, you can use a pre-configured template that includes all the essential packages and modules you need to get started.
Here are some of the benefits of using Express Boilerplate:

Speeds Up Development

Express Boilerplate provides a solid foundation for building web applications, allowing you to get up and running quickly. By using a pre-configured boilerplate, you can skip the tedious and time-consuming process of setting up the same basic configuration for every project.

Consistent Codebase

Using a boilerplate can help ensure consistency in your codebase. With a pre-configured template, you can be sure that your projects are built with the same structure and best practices every time. This can be especially useful if you work on a team or collaborate with others on projects.

Best Practices Included

Express Boilerplate includes best practices for web development out of the box. It comes pre-configured with packages and modules that are commonly used in web development, so you don't have to worry about making sure you're using the best tools for the job.

How To Use Express Boilerplate?

Using Express Boilerplate is easy! Simply follow these steps:
  • Clone the repository from GitHub:
git clone https://github.com/hagopj13/node-express-boilerplate.git
  • Install the dependencies:
cd node-express-boilerplatenpm install
  • Start the server:
npm start
That's it! You now have a fully functioning Express.js application up and running.
Boilerplate Github Post
Boilerplate Github Post

Customizing Express Boilerplate

While Express Boilerplate provides a solid foundation for building web applications, you'll likely want to customize it to suit your specific needs. Here are some tips for customizing Express Boilerplate:

Adding Routes

To add new routes to your application, simply create a new file in the routes directory and define your route handlers. For example, if you want to create a new route for /users, you could create a file called users.js in the routes directory and define your route handlers like this:
const express = require('express');
const router = express.Router();
router.get('/', (req, res) => {
// Handle GET request for /users
});
router.post('/', (req, res) => {
// Handle POST request for /users
});
module.exports = router;
Then, in the app.js file, you can require the users.js file and use it as middleware for the /users route:
const usersRouter = require('./routes/users');
app.use('/users', usersRouter);

Adding Middleware

To add new middleware to your application, simply create a new file in the middleware directory and define your middleware function. For example, if you want to create a middleware function that logs the request method and URL for every incoming request, you could create a file called logger.js in the middleware directory and define your middleware function like this:
const logger = (req, res, next) => {
console.log(`${req.method} ${req.url}`);
next();
};
module.exports = logger;
Then, in the app.js file, you can require the logger.js file and use it as middleware for all routes:
const logger = require('./middleware/logger');
app.use(logger);

Adding Packages

To add new packages to your application, simply install them using npm and require them in your code as needed. For example, if you want to add the jsonwebtoken package to your application for handling JSON Web Tokens, you could install it using npm like this:
npm install jsonwebtoken
Then, in your code, you can require the package and use it as needed:
const jwt = require('jsonwebtoken');
// Generate a new token
const token = jwt.sign({ userId: 123 }, 'secret');
// Verify a token
const decoded = jwt.verify(token, 'secret');

Changing Configuration

Express Boilerplate comes with a default configuration file located in the config directory. If you need to change any configuration settings, simply modify this file to suit your needs.
For example, if you want to change the MongoDB connection string, you can modify the databaseUrl property in the config.js file:
module.exports = {
databaseUrl: 'mongodb://localhost/my-database',
// Other configuration settings...
};

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Configuring Passport For Authentication In Express Boilerplate

Authentication is a crucial aspect of many web applications. Passport is a popular authentication middleware for Node.js that makes it easy to add authentication to your application. In this section, we'll look at how to configure Passport in Express Boilerplate.
To get started with Passport, you'll need to install the necessary packages:
npm install passport passport-local passport-jwt bcryptjs
  • passport- The main Passport module.
  • passport-local- A Passport strategy for authenticating with a username and password.
  • passport-jwt - A Passport strategy for authenticating with JSON Web Tokens (JWTs).
  • bcryptjs- A library for hashing and salting passwords.
Once you have installed the packages, you can begin configuring Passport in your application. Here are the general steps:
  • Initialize Passport in your application and add it as middleware.
  • Define Passport strategies for local authentication and JWT authentication.
  • Define middleware functions for handling authentication and authorization.
With these steps, you'll be able to add authentication to your application using Passport.

Writing Unit Tests For Your Express Application

Unit testing is an essential part of any software development process. It allows you to test individual units of code in isolation, ensuring that they function correctly. In Express Boilerplate, you can write unit tests using popular testing frameworks like Mocha and Chai.
To get started with unit testing in Express Boilerplate, you'll need to install the necessary packages:
npm install mocha chai chai-http sinon
  • mocha - A popular testing framework for Node.js.
  • chai - A library for writing assertions in JavaScript.
  • chai-http - A plugin for Chai that allows you to make HTTP requests.
  • sinon - A library for creating spies, stubs, and mocks.
Once you have installed the packages, you can begin writing unit tests for your application. Here are the general steps:
  • Define your test suites and test cases using Mocha.
  • Use Chai assertions to define the expected behavior of your code.
  • Use Chai-HTTP to make HTTP requests and test the response.
  • Use Sinon to create spies, stubs, and mocks for testing complex code.
With these steps, you'll be able to write comprehensive unit tests for your Express application.

Handling Errors In Your Express Application

Error handling is a crucial aspect of any web application. In Express Boilerplate, you can use middleware functions to handle errors and provide appropriate responses to clients.
There are two types of errors you may encounter in your Express application:
  • Synchronous errors- These errors occur during the execution of synchronous code, such as a syntax error or a failed database query.
  • Asynchronous errors- These errors occur during the execution of asynchronous code, such as a rejected Promise or a thrown error in a callback function.
To handle errors in your Express application, you can define error-handling middleware functions. These functions should be defined after your application's other middleware functions.
Here are the general steps for handling errors in Express Boilerplate:
  • Define error-handling middleware functions using the app.use method.
  • Use the next function to pass errors to the error-handling middleware.
  • Define error-handling middleware functions with four parameters: err, req, res, and next.
  • Use the err parameter to handle errors and provide an appropriate response to the client.
With these steps, you'll be able to handle errors in your Express application and provide a more robust experience for your users.

People Also Ask

Can I Add My Own Custom Middleware Functions In Express Boilerplate?

Yes, simply create a new file in the "middleware" directory and define your middleware function.

What Is The Purpose Of Mongoose In Express Boilerplate?

Mongoose is an ODM library for MongoDB that provides a higher level of abstraction than the MongoDB driver.

How Do I Handle File Uploads In Express Boilerplate?

Use the "multer" middleware to handle file uploads in your application.

Is It Possible To Containerize My Express Boilerplate Application With Docker?

Yes, Docker can be used to containerize your application for easy deployment and scalability.

How Do I Debug My Express Boilerplate Application With Visual Studio Code?

Use the built-in debugging tools in Visual Studio Code, including setting breakpoints and stepping through code.

Conclusion

Express Boilerplate is an excellent starting point for building web applications with Node.js and Express.js. It provides a solid foundation for your application, including essential packages and modules that are commonly used in web development.
By using a boilerplate, you can speed up development, ensure consistency in your codebase, and benefit from best practices included out of the box. And with its modular architecture, Express Boilerplate is highly customizable, making it suitable for a wide range of web development projects.
So why not give Express Boilerplate a try on your next web development project? With its easy setup and excellent features, you'll be up and running in no time.
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