How can you handle error responses in Express for cleaner error reporting?
- Using the throw statement
- Using the try...catch block
- Implementing custom error handling middleware
- Ignoring errors for cleaner logs
To handle error responses in Express for cleaner error reporting, you can implement custom error handling middleware. This middleware can catch errors and provide a standardized way to handle and respond to them, improving error reporting and debugging.
How can you match routes with a specific pattern in Express.js?
- app.pattern('/route', callback)
- app.match('/route', callback)
- app.use('/route', callback)
- app.get('/route', callback)
In Express.js, you can use the app.get('/route', callback) method to match routes with a specific pattern. The get method is used to handle HTTP GET requests and is often used to define routes with specific patterns. The other options do not represent the standard way to define route patterns in Express.js.
To handle HTTP POST requests in Express, you would use the ______ method.
- GET
- POST
- PUT
- DELETE
To handle HTTP POST requests in Express, you would use the POST method. The POST method is used for submitting data to be processed to a specified resource.
How does Content Security Policy (CSP) help in preventing XSS attacks, and what are its limitations?
- CSP restricts the usage of third-party libraries
- CSP blocks all JavaScript execution
- CSP defines rules for resource loading and script execution
- CSP is ineffective against XSS attacks
Content Security Policy (CSP) helps prevent Cross-Site Scripting (XSS) attacks by defining rules for resource loading and script execution in web applications. It can restrict the sources from which scripts can be executed, mitigating the risk of malicious script injection. However, CSP has limitations, such as its inability to prevent all forms of XSS attacks, the need for careful configuration, and potential compatibility issues with legacy code.
How does JavaScript handle implicit data type conversion?
- JavaScript automatically converts data types when performing certain operations, which can lead to unexpected results.
- JavaScript throws errors when trying to perform operations on different data types.
- JavaScript prohibits implicit data type conversion to ensure data consistency.
- JavaScript only allows explicit data type conversion using built-in functions.
JavaScript performs implicit data type conversion, also known as type coercion, when operators or functions are used with values of different data types. This can lead to unexpected behavior, so it's important to understand how type coercion works in JavaScript.
Developers can use npm deprecate [@] to mark a package or a specific version as deprecated, displaying a warning message ______ to any developers installing it.
- internally
- externally
- globally
- locally
When using npm deprecate, the correct option is externally. This means that a deprecation warning message will be displayed to any developers installing the package from outside the project.
How can the design of the Event Loop and Non-Blocking I/O lead to potential pitfalls in application behavior, such as callback hell or race conditions?
- The design ensures that such pitfalls are impossible in Node.js applications.
- Callback hell and race conditions are unrelated to the Event Loop and Non-Blocking I/O.
- Callback hell can occur due to deeply nested asynchronous callbacks, making code hard to read and maintain. Race conditions can happen when multiple asynchronous operations access shared resources without proper synchronization.
- Non-Blocking I/O eliminates all potential issues.
The design of the Event Loop and Non-Blocking I/O in Node.js can lead to challenges in application development. Callback hell can occur when developers create deeply nested asynchronous callbacks, making code hard to read and maintain. Race conditions can arise when multiple asynchronous operations access shared resources without proper synchronization, potentially leading to unexpected behavior. Understanding these pitfalls is crucial for writing efficient Node.js applications.
How can you create a private variable inside a JavaScript function?
- Use the 'private' keyword before declaring a variable.
- Declare the variable inside a function using 'var'.
- Use a function closure to encapsulate the variable within the function's scope.
- Use 'let' or 'const' to declare the variable inside a function.
To create a private variable in JavaScript, you can use a function closure. By defining a variable inside a function and not exposing it outside the function's scope, you can achieve encapsulation and create a private variable that is inaccessible from outside the function.
In JavaScript, the Symbol data type was introduced in ________.
- ECMAScript 2015 (ES6)
- JavaScript 1.5
- Node.js v10
- ESNext
The Symbol data type was introduced in ECMAScript 2015 (ES6). It allows you to create unique and immutable values that can be used as object property keys.
In Express.js, middleware functions have access to the request object, the response object, and the ______ function.
- next()
- send()
- app()
- router()
In Express.js, middleware functions have access to the request object (req), the response object (res), and a callback function commonly named next(). The next() function is used to pass control to the next middleware function in the chain.