When using the Buffer.concat(list[, totalLength]) method in Node.js, if the totalLength is not provided, it is calculated from the ______ of the buffers in the list.
- length
- size
- capacity
- content
When totalLength is not provided, the Buffer.concat method calculates it based on the length of the buffers in the list. The length represents the number of bytes in each buffer being concatenated.
Which feature in Pug allows for writing reusable and maintainable code?
- Mixins
- Extends
- Includes
- Blocks
In Pug, the mixins feature allows you to write reusable and maintainable code. Mixins are similar to functions and can be called to generate HTML markup with parameters, making your code more modular and easier to maintain. The other options are used for different purposes in Pug templates.
Which method of the http module is used to create an HTTP server in Node.js?
- http.createServer()
- http.createHTTPServer()
- http.newServer()
- http.initServer()
In Node.js, you create an HTTP server using the http.createServer() method. This method returns an instance of the HTTP server that can listen for incoming HTTP requests. The other options do not exist in the http module.
You notice that the application behaves differently in the development and production environments. You suspect that it is due to a difference in the package versions being used. How would you investigate and resolve this discrepancy?
- Manually compare package.json files
- Use a dependency management tool like Yarn
- Check for environment-specific configuration files
- Use a lockfile like package-lock.json
To investigate and resolve differences in package versions, you should start by manually comparing the package.json files in your development and production environments. This will help you identify discrepancies in dependencies and their versions. Option (2) suggests using an alternative package manager, which may not directly address version discrepancies. Option (3) is relevant but doesn't specifically address package version differences. Option (4) is about lockfiles, which can help ensure consistent installations but won't directly highlight version discrepancies.
What is the significance of the 'backpressure' concept in streams in Node.js?
- Backpressure ensures that data is not lost when reading from or writing to a stream.
- Backpressure prevents data from being written to a stream.
- Backpressure is a measure of stream performance.
- Backpressure is used to close streams automatically.
The significance of 'backpressure' in streams is that it ensures that data is not lost when reading from or writing to a stream. It allows the consumer of data to control the rate of data flow, preventing buffer overflow and resource exhaustion. The other options do not accurately describe the concept of 'backpressure.'
You are creating a function that accepts an arbitrary number of arguments and returns an array of those arguments. How would you use the rest operator in this scenario to collect all the passed arguments?
- (function(...args) { return args; })
- (function(args) { return args; })
- (function([...args]) { return args; })
- (function() { return ...args; })
To create a function that accepts an arbitrary number of arguments and returns an array of those arguments, you would use the rest parameter syntax (...args) in the function's parameter list. This syntax collects all the passed arguments into an array named args. The other options are either incorrect or do not use the rest operator correctly.
The spread operator can be used to merge two ______ into a new one, combining their properties.
- Arrays
- Objects
- Strings
- Functions
The spread operator can be used to merge two "Objects" into a new one, combining their properties. It's a useful way to create a new object with properties from multiple source objects.
What is the main purpose of using mocking in unit testing?
- To simulate the behavior of external dependencies
- To improve code readability
- To optimize code execution
- To enforce code standards
Mocking in unit testing is primarily used to simulate the behavior of external dependencies, such as databases, APIs, or services, so that the unit being tested can be isolated and tested in isolation. This helps ensure that tests focus on the unit's logic without relying on the actual external dependencies.
The aud claim in a JWT token represents the ________ for which the JWT is intended.
- Audience
- Issuer
- Expiration
- Subject
The "aud" (audience) claim in a JWT (JSON Web Token) represents the intended audience for which the JWT is intended. It specifies the recipients or systems that are expected to process the token. The "iss" (issuer) claim (Option 2) identifies the entity that issued the token. The "exp" (expiration) claim (Option 3) indicates the time after which the token should not be accepted. The "sub" (subject) claim (Option 4) typically identifies the subject of the token, often the user or system the token represents.
In JavaScript, the ______ method is used to iterate over all enumerable properties of an object.
- for loop
- forEach
- while loop
- iterate
The forEach method is used in JavaScript to iterate over all enumerable properties of an object. It is commonly used with arrays to perform an action on each item. The for loop and while loop are general looping constructs and not specific to object iteration. iterate is not a standard method.