In JavaScript, altering an object’s prototype at runtime can lead to ______ performance impacts.
- Positive
- Negative
- No
- Minimal
In JavaScript, altering an object's prototype at runtime can lead to "Negative" performance impacts. Modifying prototypes at runtime can cause performance bottlenecks, as it can affect the behavior of all objects that share the same prototype. It's generally recommended to avoid such runtime modifications for performance reasons.
What is the difference between the == and === operators in JavaScript?
- == compares values for equality, === compares values and types for equality
- == compares values and types for equality, === compares values for equality
- == is used for assignment, === is used for comparison
- == performs a deep comparison, === performs a shallow comparison
In JavaScript, == (loose equality) compares values for equality but performs type coercion if the operands have different types. === (strict equality) compares both values and types for equality without type coercion. Option 1 correctly describes this important distinction.
In Pug, to extend a layout, you use the extends keyword and to fill a block within the layout, you use the ______ keyword.
- include
- fill
- block
- insert
In Pug, the extends keyword is used to extend a layout, and the block keyword is used to fill a block within the layout. This allows you to create modular and reusable templates. The other options do not serve the same purpose in Pug.
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.
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.
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.