JavaScript & Express.js Fundamentals

What is JavaScript?

• JavaScript is a type of fruit

• JavaScript is a type of car

• JavaScript is a type of coffee

• JavaScript is a programming language used for web development.

What is Express.js?

• Express.js is a programming language.

• Express.js is a front-end framework for React.

• Express.js is a database management system.

• Express.js is a web application framework for Node.js.

Explain the difference between synchronous and asynchronous programming in JavaScript.

• Synchronous programming allows code to run without waiting, while asynchronous programming runs code sequentially and blocks.

• Asynchronous programming is more prone to errors compared to synchronous programming.

• Synchronous programming and asynchronous programming are the same concept.

• Synchronous programming runs code sequentially and blocks, while asynchronous programming allows code to run without waiting.

How do you handle errors in Express.js?

• Create an error-handling middleware function with four parameters (err, req, res, next) and use it with app.use(). Inside the middleware, check for errors and send an appropriate response.

• Ignore errors and let the application crash

• Use a try-catch block in each route handler to catch errors

• Manually log errors to the console without handling them

What is middleware in Express.js?

• Middleware in Express.js is only used for handling static files

• Middleware in Express.js is a function that has access to the request and response objects. It can execute any code, make changes to the request and response objects, end the request-response cycle, and call the next middleware function in the stack.

• Middleware functions in Express.js cannot modify the request or response objects

• Middleware is a built-in feature of Express.js that cannot be customized

Explain the concept of routing in Express.js.

• Routing in Express.js involves defining routes with specific HTTP methods and associated callback functions to handle client requests.

• Routing in Express.js is the same as routing in React.js.

• Express.js does not support routing functionality.

• Routing in Express.js involves defining routes with specific CSS styles.

What is the purpose of package.json in a Node.js project?

• To track project history

• To store user input data

• To display project output

• To manage project dependencies, scripts, metadata, and configuration settings.

How can you serve static files in Express.js?

• app.use(express.static('public'))

• express.useStatic('public')

• app.static('public')

• app.use(express.static('files'))

What is the role of npm in JavaScript development?

• npm simplifies package management, facilitates code sharing, and automates tasks in JavaScript development.

• npm is used for front-end development only

• npm is a version control system

• npm is a programming language

What are callbacks in JavaScript?

• Conditional statements in JavaScript

• Variables that store data in JavaScript

• Functions that are passed as arguments to other functions to be executed later.

• HTML elements in JavaScript