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Express.js middleware functions have access to the ______ object, the ______ object, and a next function in their callback function parameters.

  • request, response
  • response, request
  • req, res
  • req, next
In Express.js middleware functions, the callback function parameters typically include req (the request object) and res (the response object). Additionally, you can use a next function to pass control to the next middleware function in the pipeline. This allows you to manipulate the request and response objects or perform actions before sending a response to the client.
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You are maintaining a server that has strict security requirements. You need to allow cross-origin requests but with stringent restrictions. How can you implement CORS to fulfill these requirements while maintaining security?

  • Set Access-Control-Allow-Origin to * and rely on server-side authentication.
  • Implement preflight requests with custom headers and allow only authorized clients.
  • Avoid using CORS and handle cross-origin requests through server-side scripting.
  • Enable CORS for all origins and use server-side IP filtering.
To implement stringent security with CORS, you should use preflight requests with custom headers to allow only authorized clients. Option A is not secure as it allows any origin. Option C suggests avoiding CORS altogether, which may not be practical. Option D relies on IP filtering, which can be bypassed.
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To install all the dependencies listed in the package.json file, the ______ command should be used.

  • npm init
  • npm add
  • npm install
  • npm create
To install all the dependencies listed in the package.json file, you should use the npm install command. It reads the dependencies specified in package.json and installs them. The other options are not used for this specific purpose.
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In Sequelize, which method is commonly used to find a single instance from the database?

  • findAll()
  • findOne()
  • findSingle()
  • fetchOne()
In Sequelize, the commonly used method to find a single instance from the database is findOne(). This method retrieves the first matching record that meets the specified criteria. The other options, findAll(), findSingle(), and fetchOne(), do not represent the standard method for retrieving a single instance in Sequelize.
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In JavaScript, a for…in loop is used to iterate over the ________ of an object.

  • properties
  • values
  • methods
  • variables
In JavaScript, a for...in loop is used to iterate over the properties of an object. It is commonly used for object iteration, and it iterates through the keys or property names of an object.
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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.
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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.
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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.
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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.
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What is the primary purpose of using ESLint in a JavaScript project?

  • Ensure code quality and enforce coding style
  • Execute JavaScript code
  • Debug JavaScript code
  • Optimize JavaScript code
ESLint is primarily used to ensure code quality and enforce coding style standards in a JavaScript project. It helps identify and fix coding style issues, potential bugs, and maintainability problems in your codebase.
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