To perform setup activities before every test case in a suite in Mocha, you can use the ______ hook.
- before
- beforeEach
- setup
- suiteSetup
In Mocha, the beforeEach hook is used to perform setup activities before every test case within a suite. It runs before each test case. The other options (before, setup, and suiteSetup) represent different hook names or are not used for this specific purpose in Mocha.
In EJS, to output data to the template, you use the <%= %> syntax, whereas to execute JavaScript code, you use the ______ syntax.
- <%# %>
- <%$ %>
- <%* %>
- <% %>
In EJS (Embedded JavaScript), you use <%= %> to output data to the template and <% %> to execute JavaScript code within the template. The other options are not valid EJS syntax.
How can you set HTTP headers in the response object when using the http module?
- response.headers = {...}
- response.setHeader(name, value)
- response.setHeaders({...})
- response.addHeader(name, value)
To set HTTP headers in the response object when using the http module, you should use response.setHeader(name, value). This method allows you to set individual headers with their corresponding values. The other options are not valid methods for setting headers.
You are optimizing an application with significant read and write operations. What considerations would you need to address while implementing caching to balance read and write efficiency?
- Cache Invalidation
- Write-Through Caching
- Expiry-Based Caching
- Write-Behind Caching
When optimizing an application with significant read and write operations, Write-Through Caching is a crucial consideration. Write-Through Caching ensures that data is both read and written to the cache and the underlying data store simultaneously, maintaining consistency. Cache Invalidation and Expiry-Based Caching are more focused on read operations, and Write-Behind Caching can lead to data inconsistency if not managed carefully.
How can closures be used to create private variables in JavaScript?
- By declaring variables with the private keyword inside a function.
- By defining variables in the global scope.
- By using the const keyword to declare variables.
- By declaring variables inside a function that is not accessible from outside the function.
Closures can be used to create private variables in JavaScript by declaring variables inside a function. These variables are not accessible from outside the function, effectively creating encapsulation and data hiding.
What is the significance of defining relationships between different entities in a database schema?
- Improving data integrity and consistency
- Reducing data retrieval time
- Simplifying query complexity
- Increasing storage efficiency
Defining relationships in a database schema is crucial for improving data integrity and consistency. Relationships help maintain referential integrity, ensuring that data remains accurate and reliable when related records are updated or deleted. While relationships can impact query complexity and storage, their primary purpose is to maintain data quality.
You are developing a function that needs to merge two objects, with the second object overwriting the properties of the first one if there is a conflict. How would you achieve this?
- Object.assign()
- Object.merge()
- Object.combine()
- Object.extend()
To merge two objects with property conflicts, you can use the Object.assign() method. It takes one or more source objects and copies their properties to a target object. If properties with the same name exist in the target object, they will be overwritten by the source object's properties.
How do you ensure that your Express app is secure and defends against common web vulnerabilities?
- Not using any middleware
- Regularly updating Express to the latest version
- Implementing security middleware, validating user inputs, and using secure coding practices
- Hiding your server's IP address
To ensure that your Express app is secure and defends against common web vulnerabilities, you should implement security middleware, validate user inputs to prevent injection attacks, and follow secure coding practices to mitigate risks. Regularly updating Express is also essential for security.
What is the primary difference between 'beforeEach' and 'beforeAll' hooks in Mocha?
- beforeEach runs once before all test cases, while beforeAll runs before each test case.
- beforeEach runs before each test case, while beforeAll runs once before all test cases.
- beforeEach runs after each test case, while beforeAll runs once before all test cases.
- beforeEach runs before each test case and has no equivalent to beforeAll.
In Mocha, the primary difference is that the beforeEach hook runs before each test case, ensuring a clean state for each test, while the beforeAll hook runs once before all test cases. This means that changes made in beforeEach won't persist between test cases, but changes in beforeAll will. The other options are incorrect regarding their behavior.
Which section in the package.json file specifies the entry point of a Node.js application?
- main
- start
- entry
- node
The main section in the package.json file specifies the entry point of a Node.js application. This is the JavaScript file that will be executed when you run your application using node. It is typically set to the main application file, e.g., index.js.
CORS is a security feature implemented by ________.
- Web browsers
- Server-side frameworks
- Client-side libraries
- Database systems
CORS (Cross-Origin Resource Sharing) is a security feature implemented by web browsers. It allows or restricts web applications running at one origin (domain) to make requests for resources located on a different origin.
What is the proper way to handle errors in EJS views?
- try-catch
- error-handler middleware
- if-else
- throw
In EJS views, the proper way to handle errors is by using error-handler middleware in your Node.js application. This middleware can catch and handle errors, allowing you to display appropriate error pages or messages in your views. The other options (try-catch, if-else, and throw) are not typically used for handling errors in EJS views.