Which of the following is the correct way to declare a variable in JavaScript?
- var x = 10;
- x := 10;
- int x = 10;
- declare x = 10;
In JavaScript, variables can be declared using the var keyword. The other options are either used in different programming languages or are not valid syntax in JavaScript.
Which of the following is the correct way to parse JSON in the body of a request in Express.js?
- app.use(express.json())
- app.use(body.parse())
- app.use(request.json())
- app.parse(json)
To parse JSON in the body of a request in Express.js, you should use app.use(express.json()). This middleware is used to parse JSON data in the request body. The other options do not represent the correct way to parse JSON in Express.js.
You are working on a project that has several outdated packages with known vulnerabilities. What approach would you take to update those packages while ensuring the stability of the project?
- Update all packages to their latest versions immediately
- Review the changelogs of outdated packages, perform incremental updates, and thoroughly test each update
- Ignore the outdated packages as they may not impact the project
- Downgrade the Node.js version to maintain package compatibility
The correct approach is to review the changelogs of outdated packages, perform incremental updates, and thoroughly test each update. This ensures that updates do not introduce breaking changes and maintain project stability.
When implementing JWT, where is the token commonly stored for subsequent requests?
- In a cookie
- In a URL query parameter
- In a request header
- In a hidden form field
In JWT (JSON Web Tokens), the token is commonly stored in a request header, specifically in the Authorization header using the Bearer scheme. This method is considered secure and widely adopted. Storing the token in a cookie or URL query parameter can have security risks.
What is the significance of a returned inner function having access to the outer function's variables even after the outer function has executed?
- It's a programming error and should be avoided.
- It has no significance; it's just a quirk of JavaScript.
- It allows data encapsulation and creates private variables, aiding in maintaining state and data privacy.
- It has no practical use in JavaScript.
The significance of a returned inner function having access to the outer function's variables after the outer function has executed is that it enables data encapsulation and the creation of private variables. This is crucial for maintaining state and data privacy in JavaScript applications.
What would happen if you do not use the express.static middleware function for serving static files?
- Static files would be served by default.
- You cannot serve static files in Express.js.
- Express.js would throw an error.
- Static files would be served but with limited caching.
If you do not use the express.static middleware function to serve static files, Express.js would not be able to serve static files by default. You need this middleware to handle static file requests. The other options are incorrect because Express.js does have the capability to serve static files, but you need to configure it properly.
Which of the following responses to a preflight request will allow a browser to make a cross-origin call to upload a file?
- Access-Control-Allow-Origin: *
- Access-Control-Allow-Methods: POST
- Access-Control-Allow-Headers: Authorization
- Access-Control-Allow-Credentials: true
To enable cross-origin file uploads, you need to set Access-Control-Allow-Credentials to true, indicating that credentials like cookies are allowed. The other options are necessary but don't specifically address file uploads.
When using stubs, the main focus is on ______ rather than on verifying interactions between objects.
- State
- Behavior
- Structure
- Performance
When using stubs in testing, the main focus is on the state of the object, such as returning predefined values, rather than on verifying interactions between objects. Stubs are used to control the behavior of the object under test without asserting specific interactions.
The OpenID Connect protocol is an extension of ______ and is used for authentication as well as identity provisioning in web applications.
- OAuth 2.0
- SAML
- JWT
- LDAP
The OpenID Connect (OIDC) protocol is indeed an extension of OAuth 2.0. It is designed to provide identity and authentication services on top of OAuth 2.0, making it a powerful tool for web application security. SAML, JWT, and LDAP are different technologies with distinct purposes.
Which of the following is a correct way to declare a function in JavaScript?
- function myFunction() => { ... }
- func myFunction() { ... }
- def myFunction() { ... }
- myFunction => { ... }
In JavaScript, functions are declared using the function keyword, followed by the function name and parentheses. The correct syntax is function myFunction() { ... }. The other options are not valid ways to declare functions in JavaScript.