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.
You need to develop a function that takes an array of numbers and returns a new array containing only the unique numbers. What approach would you use to filter out the duplicates?
- Using a for loop and checking uniqueness manually
- Using Array.prototype.filter() and a custom filter function
- Using Array.from(new Set(array))
- Using Array.prototype.reduce() with a custom accumulator function
To filter out duplicate numbers in an array, you can use Array.from(new Set(array)). This creates a Set from the array (which only keeps unique values) and then converts it back to an array. It's a concise and efficient approach for this task.
How can you allocate a buffer of a specified size without initializing it in Node.js?
- Buffer.alloc(size)
- Buffer.create(size)
- Buffer.new(size)
- Buffer.allocate(size)
To allocate a buffer of a specified size without initializing it in Node.js, you should use the Buffer.alloc(size) method. It allocates a new buffer of the given size and initializes it with zeros. The other options are not valid methods for achieving this.
Which caching strategy involves keeping the most recently used items?
- LRU (Least Recently Used)
- FIFO (First In, First Out)
- Random Replacement
- LFU (Least Frequently Used)
The caching strategy that involves keeping the most recently used items is called LRU, which stands for "Least Recently Used." In LRU caching, when the cache is full and needs to make space for a new item, it removes the least recently accessed item. This strategy is often used to maximize cache efficiency.
The else if statement is used in JavaScript for ________.
- conditional execution
- error handling
- multiple comparisons
- branching based on multiple conditions
The else if statement in JavaScript is used for branching based on multiple conditions. It allows you to check additional conditions if the previous if condition is false.
You are tasked with creating tests for a complex system with multiple interacting components. How would you decide which components to mock or stub to achieve a balance between test isolation and reliability?
- Mock all components to ensure complete isolation
- Stub only the most complex components
- Mock components that are external or slow
- Stub components that are stable and well-tested
When testing a complex system, it's essential to strike a balance between test isolation and reliability. Mocking all components can lead to over-fragmented tests and make maintenance difficult. Stubbing only the most complex components may not ensure adequate coverage. To achieve this balance, you should mock components that are external or slow, as these can introduce variability and slow down tests. Stubbing components that are stable and well-tested can help reduce unnecessary complexity and speed up test execution.
What does the process object in Node.js primarily provide information about?
- Operating system processes
- Web browser processes
- File I/O processes
- Database processes
The process object in Node.js primarily provides information about operating system processes. It allows you to interact with and control the Node.js process, such as accessing command line arguments, environment variables, and exiting the process. It is not related to web browser, file I/O, or database processes.
When designing systems with Non-Blocking I/O, careful consideration must be given to avoid ________, where multiple asynchronous operations are competing for resources.
- Callback Hell
- Deadlock
- Blocking I/O
- Synchronous Execution
When designing systems with Non-Blocking I/O, careful consideration must be given to avoid "Callback Hell," also known as "Callback Pyramid" or "Callback Spaghetti." This occurs when multiple asynchronous operations are nested deeply, making code difficult to read and maintain.
How can you implement template inheritance in Pug?
- extend layout.pug
- include layout.pug
- inherit layout.pug
- template layout.pug
In Pug, template inheritance is implemented using the extend keyword followed by the name of the layout file. This allows child templates to inherit the structure and content of the specified layout file. The other options (include, inherit, and template) are not used for template inheritance in Pug.