How can a Refresh Token be utilized effectively in maintaining user sessions securely in a web application?
- A refresh token can be used to generate new access tokens without requiring the user to re-enter their credentials.
- A refresh token can be used to store user session data on the client-side.
- A refresh token can be used as the primary authentication method for users.
- A refresh token can be shared publicly without security concerns.
A refresh token is a long-lived token that can be used to obtain a new access token after the previous one expires. It should be kept secret and securely stored on the client side. It enhances security by reducing the need to store access tokens, which have shorter lifespans, on the client.
Which of the following JavaScript properties allows an object to inherit properties from another object?
- inherit
- copy
- prototype
- extend
In JavaScript, the prototype property is used to allow an object to inherit properties from another object. When an object is created, it inherits properties and methods from its prototype, which can be another object. This forms the basis of prototype-based inheritance in JavaScript. The other options are not standard properties used for inheritance.
Which of the following is a common tool used for benchmarking Node.js applications?
- NPM
- Mongoose
- Apache
- Apache Benchmark (ab)
Apache Benchmark (ab) is a common tool used for benchmarking Node.js applications. It allows you to measure the performance and concurrency of your Node.js server by simulating multiple requests. NPM and Mongoose are not benchmarking tools, and Apache is not typically used for Node.js benchmarking.
The process of an object gaining access to properties and methods of another object through the prototype chain is known as ______.
- Inheritance
- Encapsulation
- Polymorphism
- Abstraction
The process of an object gaining access to properties and methods of another object through the prototype chain is known as "Inheritance." In JavaScript, objects inherit properties and methods from their prototypes in a chain-like fashion. This allows for code reuse and is a fundamental concept in object-oriented programming.
How can you serve multiple static directories using Express.js?
- app.static('directory1'); app.static('directory2');
- app.use(express.static('directory1')); app.use(express.static('directory2'));
- app.static('directory1, directory2');
- app.use(express.static(['directory1', 'directory2']));
To serve multiple static directories in Express.js, you should use the express.static middleware function multiple times with different directory paths. This allows you to specify and configure each static directory separately. The other options are not valid syntax for serving multiple static directories.
A well-designed schema in a relational database typically involves the use of ________ to ensure that relationships between tables are maintained.
- Foreign Keys
- Indexes
- Stored Procedures
- Triggers
A well-designed schema in a relational database typically involves the use of "foreign keys" to ensure that relationships between tables are maintained. Foreign keys establish referential integrity, ensuring that data in one table corresponds to data in another table, maintaining the integrity of the database relationships.
Which of the following HTTP headers is crucial for preventing Cross-site Scripting (XSS) attacks?
- Content-Encoding
- Access-Control-Allow-Origin
- X-Frame-Options
- User-Agent
The HTTP header crucial for preventing Cross-site Scripting (XSS) attacks is X-Frame-Options. This header prevents a web page from being embedded within an
How does the fs Promises API differ from the callback-based API in handling errors?
- Promises API throws errors synchronously
- Callback API requires try-catch for errors
- Promises API uses async/await for error handling
- Callback API returns errors as the last argument
The fs Promises API differs from the callback-based API by using async/await for error handling. In the Promises API, you can use try-catch to catch errors, making error handling more similar to synchronous code. The callback API, on the other hand, returns errors as the last argument to the callback function.
How should developers properly handle unhandled promise rejections in Node.js?
- Using a global event listener for 'unhandledRejection' events.
- Ignoring unhandled promise rejections.
- Manually catching every promise rejection.
- Using try...catch for all promises.
Properly handling unhandled promise rejections in Node.js involves using a global event listener for 'unhandledRejection' events. This allows developers to log or handle unhandled promise rejections globally, which is crucial for preventing silent errors in applications. Ignoring rejections or manually catching every promise rejection can lead to unexpected and unhandled errors. Using try...catch for all promises is not practical in large applications.
You are designing a RESTful API and want to ensure that it is secure against injection attacks, what are the various considerations and practices you would implement to sanitize and validate input data?
- Use parameterized queries and prepared statements.
- Implement input validation and sanitize user inputs.
- Avoid using HTTPS for data transmission.
- Rely on client-side validation for security.
Option (1) is correct. Parameterized queries and prepared statements help prevent SQL injection attacks. Option (2) is also correct, as input validation and sanitation are important for protecting against various injection attacks. Options (3) and (4) are incorrect and insecure practices.