You are implementing error handling in an Express application, and you notice that asynchronous errors are not being caught by your error-handling middleware. How should you modify your error-handling approach to ensure that asynchronous errors are caught?
- Wrap asynchronous code with try-catch blocks
- Use the next function with async/await middleware
- Disable asynchronous error handling
- Increase the Node.js event loop size
In Express.js, asynchronous errors are not automatically caught by synchronous error-handling middleware. To catch asynchronous errors, you should use the next function with async/await middleware to ensure that errors occurring in asynchronous code are properly handled by your error-handling middleware. Wrapping asynchronous code with try-catch blocks won't work for middleware functions.
JavaScript’s ______ operator can be used to create a new object with the specified prototype object and properties.
- New
- Prototype
- Object.create()
- Construct
JavaScript's "Object.create()" operator can be used to create a new object with the specified prototype object and properties. This method is commonly used for creating objects with specific prototypes in JavaScript, allowing for more control over inheritance and object composition.
In Express.js, how does the order in which routes are defined affect the routing mechanism?
- Routes are matched in a random order
- Routes are matched in the order they are defined
- Routes are matched in reverse order
- Routes are matched based on alphabetical order
In Express.js, the order in which routes are defined affects the routing mechanism. Routes are matched in the order they are defined, and the first matching route is executed. This means that the order of route definitions is crucial as it determines which route will handle a request.
What is the primary purpose of implementing CORS in web development?
- Allow cross-origin requests
- Improve website performance
- Enhance security
- Prevent JavaScript errors
The primary purpose of implementing CORS (Cross-Origin Resource Sharing) in web development is to allow cross-origin requests. CORS is a security feature that permits or restricts web pages in one domain from making requests to a different domain, enhancing security by preventing unauthorized access to resources while enabling legitimate cross-origin communication.
What does the 'major' number in a semantic versioning format (e.g. 1.2.3) typically represent?
- Major changes
- Minor changes
- Patch changes
- Build number
In semantic versioning (SemVer), the 'major' number represents significant changes that are not backwards-compatible. This means that if the 'major' version number increases, it indicates that there have been substantial changes in the software that may break compatibility with previous versions.
What is the difference between a static import and a dynamic import in JavaScript?
- Static import is used to load modules at compile time, and it's part of the ES6 module system.
- Dynamic import is used to load modules at runtime, and it returns a promise that resolves to the module.
- Static import is used for loading ES6 modules, while dynamic import is used for CommonJS modules.
- There is no difference between static and dynamic imports in JavaScript.
Static imports are used at compile time and load modules synchronously, while dynamic imports are used at runtime and load modules asynchronously. Dynamic imports return a promise that resolves to the module.
For optimizing complex queries involving multiple JOIN operations, one can use ________ to break them into simpler ones.
- Subqueries
- Indexes
- Caching
- Temporary Tables
For optimizing complex queries involving multiple JOIN operations, one can use "Subqueries" to break them into simpler, more manageable queries. Subqueries allow you to retrieve intermediate results that can be used in the main query.
What is the significance of the order in which middlewares are defined in Express.js?
- The order of middleware does not matter; Express.js automatically arranges them.
- Middlewares are executed in the reverse order of definition.
- Middlewares are executed in the order of definition.
- Middleware order depends on the priority given when defining routes.
In Express.js, middlewares are executed in the order they are defined. The order matters because each middleware can modify the request or response objects and pass them on to the next middleware.
In Express.js, to limit the middleware execution to a particular HTTP method, you should use the ______ method.
- app.use()
- router.use()
- app.method()
- router.method()
To limit the execution of middleware to a specific HTTP method in Express.js, you should use the router.use() method and specify the HTTP method as an argument, such as router.use('GET', middlewareFunction). This ensures that the middleware is only executed for requests with the specified method.
You are tasked with ensuring that a web application works seamlessly and that all components interact as expected. Which testing approach would be most suitable to verify the interactions between different components and services?
- Unit Testing
- Integration Testing
- Functional Testing
- Usability Testing
To verify interactions between different components and services in a web application, Integration Testing is the most suitable approach. Unit Testing focuses on individual units of code, Functional Testing checks if the application meets its specifications, and Usability Testing focuses on user experience. Integration Testing is specifically designed to test the interactions between components.