How does JavaScript's dynamic typing affect variable assignments and operations?
- It enforces strict type checking.
- It allows variables to change type during runtime.
- It requires explicit type annotations for all variables.
- It prevents type errors at compile time.
JavaScript's dynamic typing allows variables to change their data type during runtime. Unlike languages with static typing, you don't need to specify the data type of a variable explicitly.
You need to expose a global utility function that should be accessible across different modules in your Node.js application. How would you leverage the global object to achieve this?
- global.utility = require('./utility');
- global.util = require('./utility');
- global.import('./utility')
- global.include('./utility')
To expose a global utility function in Node.js, you can use global.utility = require('./utility');. This allows you to require the module once and make it accessible globally across different modules. The other options do not achieve this in the correct way.
When would you use export default over named exports in a module?
- export default is used when you want to export multiple values from a module as an object with named keys.
- export default is used when you want to export a single value, function, or class from a module.
- export default is used when you want to export a module without specifying a name for it.
- export default is used when you want to create a private module that can't be imported from other modules.
export default is used when you want to export a single value, function, or class as the default export of a module. This allows you to import it using any name you prefer when importing. Named exports are used when you want to export multiple values with specific names.
What does the return statement do in a JavaScript function?
- Returns a value from the function and exits the function
- Declares a variable
- Creates a loop
- Includes a comment in the code
The return statement in a JavaScript function is used to return a value from the function and immediately exit the function. It is used to send data back to the caller of the function. The other options do not describe the purpose of the return statement.
You are integrating ESLint into a legacy project. How would you approach linting the existing codebase without disrupting the development workflow?
- Lint the entire codebase in one go and fix all issues immediately.
- Gradually introduce ESLint, starting with new code and addressing legacy code issues incrementally.
- Disable ESLint for the legacy code and only apply it to new code.
- Ignore linting in legacy projects as it can't be easily integrated.
To avoid disruption, it's best to gradually introduce ESLint. Start by applying it to new code and address legacy code issues incrementally. Linting the entire codebase at once might be overwhelming and disruptive. Disabling ESLint for legacy code or ignoring it is not a recommended approach for maintaining code quality.
You are developing an application with multiple user roles, and each role has different levels of access to resources. How would you securely implement role-based access control to prevent unauthorized access?
- Use JSON Web Tokens (JWT) to manage user sessions and roles.
- Implement access control lists (ACLs) in your application.
- Check the user's role in the frontend to determine access.
- Rely solely on server-side sessions to control access.
Option (1) is correct. Using JWTs for session management and roles is a secure approach as they are self-contained and can be verified without relying on server-side sessions. Options (2) and (4) are less secure and may lead to vulnerabilities. Option (3) is incorrect as access control should be enforced on the server.
How can you remove a listener from an event using the Events module in Node.js?
- event.removeListener(event, listener)
- event.remove(listener)
- event.off(event, listener)
- listener.remove(event)
To remove a listener from an event using the Events module in Node.js, you should use the event.removeListener(event, listener) method. This method takes the event name and the listener function as arguments and removes the specified listener from the event. The other options are not valid methods for removing listeners.
When the Event Loop encounters an asynchronous task, it offloads it to the ________ and continues to execute subsequent tasks.
- Callback Queue
- Worker Thread
- Event Emitter
- Main Memory
When the Event Loop encounters an asynchronous task, it offloads it to the Callback Queue and continues to execute subsequent tasks. These tasks are then processed from the Callback Queue when the main thread is available.
Which of the following ESLint rules enforces consistent indentation in your code?
- no-console
- indent
- semi
- no-unused-vars
The indent rule in ESLint enforces consistent indentation in your code. It helps ensure that your code is properly formatted and readable by specifying the expected indentation style. The other options are for different rules, such as preventing the use of console, enforcing semicolons, or catching unused variables.
What is the first argument typically passed to a callback function in Node.js to handle errors?
- result
- data
- error
- callback
The first argument typically passed to a callback function in Node.js to handle errors is error. This argument holds information about any errors that may have occurred during the asynchronous operation. The other options (result, data, and callback) are used for different purposes in callback functions.