What happens to the Event Loop when the callback queue and the task queue are both not empty?
- It suspends the Event Loop until both queues are empty.
- It processes callbacks from the callback queue before tasks from the task queue.
- It processes tasks from the task queue before callbacks from the callback queue.
- It randomly selects items to process from both queues.
When both the callback queue and the task queue are not empty, the Event Loop in Node.js follows a specific order. It first processes callbacks from the callback queue before moving to tasks from the task queue. This order ensures that callback functions, which often include I/O operations, are handled promptly.
In Node.js, how can data be written to a writable stream?
- Using the read() method
- Using the write() method
- Using the pipe() method
- Using the readable() method
Data can be written to a writable stream in Node.js using the write() method. This method allows you to write data to the stream, which can be a file, network connection, or any other writable destination. The pipe() method is used for piping data from a readable stream to a writable stream, and the other options are not the correct ways to write data to a writable stream.
To perform an action once a Promise is settled, regardless of its outcome, you can use the .finally() method, which is called on the ________ of a Promise.
- rejection
- resolution
- completion
- termination
To perform an action once a Promise is settled, regardless of whether it's fulfilled or rejected, you can use the .finally() method. This method is called on the "completion" of a Promise. It's often used for cleanup operations.
You are tasked with implementing an authentication system for your Express API. What considerations should you make regarding security, user experience, and scalability when choosing an authentication strategy?
- Use JWT (JSON Web Tokens) with long expiration times.
- Store plain text passwords in the database.
- Implement OAuth 2.0 for social login only.
- Use basic authentication over HTTP.
Using JWT with long expiration times might seem like a convenient option for user experience, but it could pose a security risk. Storing plain text passwords is a severe security vulnerability. Implementing OAuth 2.0 for social login only might not be sufficient for all authentication needs. Using basic authentication over HTTP is not secure. A robust authentication strategy should consider security (option 1) without compromising user experience and
You are building a dynamic form generator. You need to ensure that the data types of the input values are preserved when sent to the server. What approach should you take for data type preservation when stringifying the inputs?
- JSON.stringify(inputs);
- inputs.toString();
- String(inputs);
- inputs.join(",");
To preserve data types when stringifying inputs, you should use JSON.stringify(inputs);. This method serializes data to a JSON string, which can later be parsed back into their original data types. The other options do not provide the same level of data type preservation.
What will happen if there are conflicting names when importing items from a module?
- The last imported item with the conflicting name will override the previous ones.
- An error will occur, and you will need to manually resolve the conflict by renaming the items.
- JavaScript will automatically assign unique names to the conflicting items.
- Conflicting names are not allowed when importing items from a module.
In JavaScript, when you import items from a module, if there are conflicting names (e.g., two imported items have the same name), the last imported item with the conflicting name will override the previous ones. This can lead to unexpected behavior and should be avoided by using unique and descriptive names for imported items.
To run a pre-hook for a custom script named "build," you would define a script named ______ in your package.json file.
- prebuild
- pre-hook
- beforebuild
- pre-build
To run a pre-hook for a custom script named "build" in your package.json file, you would define a script named prebuild. This allows you to execute tasks before the "build" script is run, such as setting up dependencies or configurations. The other options do not follow the standard naming convention for npm pre-hooks.
What is the purpose of the res.send() method in Express?
- To send a response to the client
- To receive data from the client
- To redirect the client to another route
- To render a view template
The res.send() method in Express is used to send a response back to the client. It is commonly used to send text, HTML, JSON, or other data as the response to an HTTP request. It is a fundamental method for responding to client requests in Express applications. The other options are not the primary purpose of res.send().
How can closures be utilized effectively for asynchronous programming in JavaScript?
- Closures are often used in asynchronous programming in JavaScript to capture variables that are needed later when an asynchronous operation completes. This helps in maintaining the context and avoiding callback hell. Closures can be used to create functions that wrap asynchronous operations, making the code more readable and maintainable.
- Closures are commonly used in asynchronous programming in JavaScript to maintain the state and context of a function across asynchronous operations. They can be used to create functions that encapsulate asynchronous logic, making code more modular and readable.
- Closures are a powerful tool in asynchronous programming in JavaScript. They can be used to capture the state and context of a function, allowing asynchronous operations to access and modify variables from their enclosing scope. This is useful for maintaining data integrity and managing complex asynchronous flows.
- In asynchronous programming in JavaScript, closures are often used to capture the state of a function and maintain context across asynchronous operations. This can help in avoiding callback hell and making asynchronous code more readable and modular.
Asynchronous Programming with Closures
How can you extract route parameters in Express.js from a route URL like "/users/:userId"?
- Using req.params.userId
- Using req.query.userId
- Using req.body.userId
- Using req.param.userId
In Express.js, you can extract route parameters using req.params.userId. Route parameters are specified in the URL path with a colon prefix, and you can access them using req.params. The other options are not the correct way to access route parameters.