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In JavaScript, a function that is defined inside another function has access to the outer function's variables, forming a ________.

  • Closure
  • Enclosure
  • Junction
  • Intersection
In JavaScript, when a function is defined inside another function, it forms a "closure." A closure allows the inner function to access the outer function's variables even after the outer function has finished executing.
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The fs.createReadStream method is particularly useful when dealing with ______ sized files.

  • small
  • large
  • binary
  • text
The fs.createReadStream method in Node.js is particularly useful when dealing with large sized files. This method allows you to efficiently read large files in smaller chunks, which can be memory-efficient for handling large datasets.
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Which of the following array methods does not mutate the original array in JavaScript?

  • splice()
  • push()
  • concat()
  • pop()
The concat() method in JavaScript creates a new array that combines the elements of the original array and the elements passed as arguments, without modifying the original array. The other methods, such as splice(), push(), and pop(), directly modify the original array.
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You are maintaining a library, and you need to release a new version that fixes a bug but also changes the behavior of an existing feature. How should you update the version number according to semantic versioning?

  • 1.0.0
  • 1.1.0
  • 2.0.0
  • 1.0.1
According to semantic versioning (SemVer), when you make backward-incompatible changes or breaking changes, you should increment the major version. In this scenario, since the behavior change affects existing users, you should update to version 2.0.0.
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What would be the best way to handle errors in an Express application when building RESTful APIs?

  • Using try...catch blocks in route handlers
  • Sending 404 Not Found for all errors
  • Using console.log() for error messages
  • Not handling errors, let them crash the server
The best way to handle errors in an Express application when building RESTful APIs is to use try...catch blocks in route handlers. This allows you to catch errors and send appropriate HTTP responses with error details. Sending 404 Not Found for all errors is not a good practice, and letting errors crash the server is even worse. Console.log() is generally used for debugging but not for handling errors.
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Using label with break or continue provides more control over which part of the code to ________ or ________ in JavaScript.

  • skip, execute
  • terminate, run
  • jump, skip
  • stop, resume
Using labels with break or continue in JavaScript provides more control over which part of the code to skip or execute. Labels allow you to specify which loop or block of code should be affected by break or continue statements when dealing with nested loops or complex control flow.
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How can you extract route parameters in Express.js from a route URL like "/users/:userId"?

  • Using req.params.userId
  • Using req.query.userId
  • Using req.body.userId
  • Using req.param.userId
In Express.js, you can extract route parameters using req.params.userId. Route parameters are specified in the URL path with a colon prefix, and you can access them using req.params. The other options are not the correct way to access route parameters.
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How can closures be utilized effectively for asynchronous programming in JavaScript?

  • Closures are often used in asynchronous programming in JavaScript to capture variables that are needed later when an asynchronous operation completes. This helps in maintaining the context and avoiding callback hell. Closures can be used to create functions that wrap asynchronous operations, making the code more readable and maintainable.
  • Closures are commonly used in asynchronous programming in JavaScript to maintain the state and context of a function across asynchronous operations. They can be used to create functions that encapsulate asynchronous logic, making code more modular and readable.
  • Closures are a powerful tool in asynchronous programming in JavaScript. They can be used to capture the state and context of a function, allowing asynchronous operations to access and modify variables from their enclosing scope. This is useful for maintaining data integrity and managing complex asynchronous flows.
  • In asynchronous programming in JavaScript, closures are often used to capture the state of a function and maintain context across asynchronous operations. This can help in avoiding callback hell and making asynchronous code more readable and modular.
Asynchronous Programming with Closures
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What is the purpose of the res.send() method in Express?

  • To send a response to the client
  • To receive data from the client
  • To redirect the client to another route
  • To render a view template
The res.send() method in Express is used to send a response back to the client. It is commonly used to send text, HTML, JSON, or other data as the response to an HTTP request. It is a fundamental method for responding to client requests in Express applications. The other options are not the primary purpose of res.send().
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To run a pre-hook for a custom script named "build," you would define a script named ______ in your package.json file.

  • prebuild
  • pre-hook
  • beforebuild
  • pre-build
To run a pre-hook for a custom script named "build" in your package.json file, you would define a script named prebuild. This allows you to execute tasks before the "build" script is run, such as setting up dependencies or configurations. The other options do not follow the standard naming convention for npm pre-hooks.
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What will happen if there are conflicting names when importing items from a module?

  • The last imported item with the conflicting name will override the previous ones.
  • An error will occur, and you will need to manually resolve the conflict by renaming the items.
  • JavaScript will automatically assign unique names to the conflicting items.
  • Conflicting names are not allowed when importing items from a module.
In JavaScript, when you import items from a module, if there are conflicting names (e.g., two imported items have the same name), the last imported item with the conflicting name will override the previous ones. This can lead to unexpected behavior and should be avoided by using unique and descriptive names for imported items.
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You are building a dynamic form generator. You need to ensure that the data types of the input values are preserved when sent to the server. What approach should you take for data type preservation when stringifying the inputs?

  • JSON.stringify(inputs);
  • inputs.toString();
  • String(inputs);
  • inputs.join(",");
To preserve data types when stringifying inputs, you should use JSON.stringify(inputs);. This method serializes data to a JSON string, which can later be parsed back into their original data types. The other options do not provide the same level of data type preservation.
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