How can debugging be enabled in an Express application for development purposes?
- Set app.debug = true;
- Use the DEBUG environment variable
- Add console.debug statements
- Call app.enable('debug');
Debugging can be enabled in an Express application for development purposes by using the DEBUG environment variable. This allows you to selectively enable debugging for specific modules or components. The other options do not enable debugging in the standard way for Express applications.
What will happen if you run npm init -y in a Node.js project directory?
- It will initialize a project with default values
- It will uninstall Node.js
- It will install all available packages
- It will create a new Node.js version
Running npm init -y in a Node.js project directory will initialize a project with default values without prompting you for input. It creates a package.json file with default settings. It does not uninstall or install Node.js or packages.
You are developing a feature to filter out invalid user inputs. Which conditional structures can be used to validate multiple conditions effectively and execute specific code blocks?
- if...else if...else statements
- switch statement
- try...catch statements
- while loop
To validate multiple conditions effectively and execute specific code blocks for filtering out invalid user inputs, you would typically use if...else if...else statements. These conditional structures allow you to check various conditions and perform different actions based on the outcome. The switch statement is more suitable for situations with a single value and multiple cases, and try...catch is primarily used for error handling. A while loop is not a conditional structure for validation but a looping mechanism.
What is the scope of a variable declared using the var keyword inside a function?
- Global scope
- Function scope
- Block scope
- Local scope
In JavaScript, a variable declared using the var keyword inside a function has function scope. This means it is accessible within the entire function but not outside of it. Unlike let and const, var does not have block scope.
In Jest, ______ is used to generate snapshot files of a component's output render.
- snapshot
- renderSnapshot
- createSnapshot
- toMatchSnapshot
In Jest, the toMatchSnapshot function is used to generate snapshot files of a component's output render. This allows you to capture the expected output and compare it to the actual output during subsequent test runs. The other options do not represent the correct Jest function for this purpose.
When installing packages using npm, where are the dependencies listed?
- In the "package.json" file under the "dependencies" section
- In the "node_modules" directory
- In the project's main JavaScript file
- In a separate "dependencies.json" file
When you install packages using npm, the dependencies are listed in the "package.json" file under the "dependencies" section. This file acts as a manifest for your project and keeps track of its dependencies.
In JWT, what part of the token is responsible for holding the user's information?
- Payload
- Header
- Signature
- Claims
In JWT (JSON Web Tokens), the user's information is typically held in the Payload. The Payload contains claims, which are statements about an entity (typically, the user) and additional data. The Header contains metadata, and the Signature is used for verification.
Which middleware is commonly used in Express.js to handle user authentication?
- express-auth
- passport
- jsonwebtoken
- authenticator
In Express.js, the commonly used middleware for handling user authentication is passport. Passport is a widely adopted authentication middleware that provides various authentication strategies for different authentication providers like local, Google, Facebook, and more. The other options are not standard authentication middleware for Express.js.
Which of the following is the correct way to declare an array in JavaScript?
- var myArray = [];
- array myArray = [];
- myArray = new Array();
- myArray = {}
The correct way to declare an array in JavaScript is by using square brackets []. So, var myArray = []; is the correct syntax. The other options are either not valid or used in different programming languages.
What considerations should be taken into account while implementing Role-Based Access Control (RBAC) in Express.js applications?
- Properly define roles and their permissions, enforce access control at the route level, and perform input validation.
- RBAC should only be implemented on the client side to avoid server overhead.
- RBAC implementation should allow any user to access any resource without restrictions.
- Roles should be hardcoded in the application without the ability to modify them.
When implementing RBAC in Express.js, it's crucial to define roles and their associated permissions, enforce access control at the route level, and perform input validation to prevent unauthorized access. The other options are incorrect as they neglect key considerations for RBAC implementation.
The ______ property of the request object in the http module contains the HTTP method of the request.
- method
- type
- httpMethod
The method property of the request object in the http module contains the HTTP method of the request. This property allows you to determine whether the request is a GET, POST, PUT, DELETE, or another HTTP method, which is important for routing and handling requests correctly.
When creating a custom readable stream in Node.js, implementing the '______' method is essential to supply the stream with data chunks.
- push
- write
- read
- pipe
When creating a custom readable stream in Node.js, implementing the 'read' method is essential to supply the stream with data chunks. This method is invoked by the stream consumer to request data. It should be implemented to push data into the stream using the 'push' method or emit 'data' events.