To specify a specific version of a package in the package.json file, you can use a ______ to define the exact version number.
- semver
- specifier
- version-lock
- exact
To specify a specific version of a package in the package.json file, you can use a semver specifier to define the exact version number or a range of versions you want to use. Semver specifiers allow for flexibility in specifying version requirements for packages.
You are tasked with optimizing a large-scale application. How would identifying and managing closures help in optimizing the application's memory usage and performance?
- Closures have no impact on memory usage and performance
- Identifying and releasing unnecessary closures can reduce memory consumption and improve performance
- Closures should be created for all functions to improve memory management
- Increasing the use of closures will automatically optimize the application
Identifying and releasing unnecessary closures (option b) can indeed reduce memory consumption and improve performance in large-scale applications. Closures do impact memory usage, and creating too many unnecessary closures can lead to memory leaks and performance issues. Options a, c, and d do not accurately describe the role of closures in optimizing applications.
How does indexing impact the performance of read and write operations in a database?
- It significantly slows down both read and write operations.
- It has no impact on read operations but speeds up write operations.
- It significantly speeds up read operations but has no impact on write operations.
- It significantly speeds up both read and write operations.
Indexing in a database can significantly speed up read operations because it allows the database system to quickly locate specific records. However, it can slightly slow down write operations because the database needs to update the index when new data is inserted or existing data is updated.
When performing CRUD operations on a database, which operation can be the most expensive in terms of performance?
- Create
- Read
- Update
- Delete
Among CRUD operations, "Update" can often be the most expensive in terms of performance. This is because updating records may require the database to search for the existing record, make changes, and write the updated data back to disk, which can be resource-intensive. Read operations are typically less expensive.
When a Promise is pending and neither fulfilled nor rejected, it is in the ________ state.
- awaiting
- undefined
- completed
- idle
When a Promise is pending and hasn't been resolved or rejected, it is in the "awaiting" state. This is the initial state of a Promise before it is settled.
What are the best practices for error handling in a large-scale Node.js application?
- Avoiding error handling altogether for performance reasons.
- Using global error handlers for unhandled errors.
- Handling errors at the lowest level of code execution.
- Logging errors but not taking any action.
In large-scale Node.js applications, best practices for error handling include handling errors at the lowest level of code execution, close to where they occur. This improves code maintainability and makes it easier to trace the source of errors. Avoiding error handling for performance reasons is a bad practice. Using global error handlers is suitable for unhandled errors, but it's essential to handle errors at the source first. Simply logging errors without taking corrective action is incomplete error handling.
You are building a RESTful API with Express to serve a mobile application. The mobile development team has asked for the ability to retrieve condensed responses to minimize data usage. How would you accommodate this request while maintaining the integrity of your API?
- Create separate endpoints for condensed and full responses.
- Use query parameters to allow clients to specify the response format.
- Disable compression to send smaller payloads.
- Use WebSocket instead of REST for real-time updates.
Using query parameters to allow clients to specify the response format is a common and RESTful approach to accommodating different client needs. Creating separate endpoints for each format can lead to redundancy and maintenance challenges. Disabling compression would likely increase, not decrease, data usage. Using WebSockets is for real-time communication and doesn't directly address response format concerns.
In what scenario would using Domain API be beneficial for error handling in Node.js?
- When handling HTTP requests in Express.js.
- When handling file I/O operations.
- When creating a RESTful API.
- When dealing with database connections.
The Domain API was deprecated in Node.js and is no longer recommended for use. It was originally designed to handle errors in scenarios like file I/O operations. However, it has been deprecated because it didn't provide a robust solution for error handling, and other mechanisms like try...catch and event listeners have become more standard for handling errors in modern Node.js applications. Using it is not advisable in any scenario.
When using a third-party storage service to store uploaded files, what is crucial to prevent unauthorized access?
- Use predictable file names and URLs for easy access.
- Share access credentials widely to simplify sharing files.
- Implement proper access controls and use signed URLs or tokens.
- Store files without any access restrictions for maximum accessibility.
When using a third-party storage service, it's crucial to prevent unauthorized access by implementing proper access controls and using mechanisms like signed URLs or tokens. This ensures that only authorized users can access the files while keeping them secure. Using predictable file names and URLs, sharing access credentials widely, or storing files without restrictions can lead to unauthorized access and security breaches.
What considerations should be made when implementing transactions in Sequelize for isolation and atomicity?
- Choosing the appropriate isolation level
- Ensuring that transactions are started manually
- Avoiding the use of nested transactions
- Setting the transaction mode to 'autocommit'
When implementing transactions in Sequelize for isolation and atomicity, you should consider choosing the appropriate isolation level based on your application's requirements. Transactions should typically be started manually, avoiding nested transactions for simplicity and maintainability. Setting the transaction mode to 'autocommit' would defeat the purpose of using transactions for atomicity.