The process.env object in Node.js contains the ________ variables of the environment where the Node.js process is executed.
- environment
- system
- user
- configuration
The process.env object in Node.js contains the environment variables of the system where the Node.js process is executed. These variables can be used to configure the behavior of the Node.js application based on the environment.
How does the placement of a package in dependencies or devDependencies affect the build process of a project?
- It has no impact on the build process; it's only for organizational purposes.
- Packages in dependencies are bundled together, while devDependencies are loaded asynchronously.
- Dependencies are loaded first and are critical for the build, while devDependencies are optional.
- Packages in devDependencies are included in the production build.
The placement of a package in dependencies or devDependencies affects the build process. Packages in dependencies are critical for the build and are loaded first, while packages in devDependencies are optional and excluded from the production build.
The method '______' is used to read data from a readable stream in Node.js.
- readData
- fetch
- read
- getData
In Node.js, the read method is used to read data from a readable stream. It allows you to retrieve data from the stream in chunks. The other options are not the correct methods for reading data from readable streams.
To run multiple npm scripts sequentially in the specified order, you can use npm run ______.
- series
- sequence
- concat
- parallel
To run multiple npm scripts sequentially, you can use the npm run command followed by the script names separated by space. The scripts will run in the order you specify, one after the other.
How can you create a custom lifecycle event that runs a series of npm scripts in a specified order?
- Use the pre and post prefixes with custom script names
- Use a third-party package like "npm-run-all"
- It's not possible to create custom lifecycle events
- Use JavaScript code within package.json
You can create a custom lifecycle event that runs a series of npm scripts in a specified order by using a third-party package like "npm-run-all." This package allows you to define complex run scripts in a convenient way, specifying the order of execution and handling dependencies between scripts.
How can you simulate user actions like clicks or keyboard inputs in Jest?
- jest.spyOn()
- jest.mock()
- jest.fn()
- jest.simulate()
In Jest, you can simulate user actions like clicks or keyboard inputs using jest.fn(). This allows you to create mock functions that can simulate user interactions and track their calls. The other options have different purposes; jest.spyOn() is used to spy on method calls, jest.mock() is used to mock modules, and jest.simulate() is not a valid Jest method for simulating user actions.
Cache ______ is a situation where multiple requests are made to a resource that is expensive to produce, causing a surge in load.
- Throttling
- Bursting
- Collapsing
- Overloading
Cache bursting is a situation where multiple requests are made to a resource that is expensive to produce, causing a surge in load. It typically occurs when cached data expires or when the cache is invalidated.
What is the primary purpose of setting up test suites in a testing framework?
- Test suites organize individual test cases into logical groups.
- Test suites improve the performance of test execution.
- Test suites make it easier to write complex test cases.
- Test suites ensure that tests are executed in random order.
Test suites in a testing framework are used to organize individual test cases into logical groups, making it easier to manage and execute tests. This helps maintain a structured and organized testing process.
You are tasked with optimizing a Node.js application suffering from frequent delays and unresponsive behavior. How would you diagnose and address potential issues related to the Event Loop and blocking operations?
- Increase the size of the Event Loop thread pool.
- Use profiling tools like Node.js built-in profiler or third-party tools like Clinic.js.
- Replace Node.js with a different runtime environment.
- Use synchronous file I/O operations for better performance.
To diagnose and address issues related to the Event Loop and blocking operations in Node.js, you should use profiling tools like Node.js built-in profiler or third-party tools like Clinic.js. These tools help you identify bottlenecks and performance issues in your code. Options a, c, and d are not recommended solutions and may lead to further issues.
In the context of testing, what is the main difference between a mock and a stub?
- Stubs are used for functions, while mocks are used for objects
- Mocks record and verify interactions, while stubs only simulate behavior
- Stubs are only used in integration tests, while mocks are used in unit tests
- Mocks are less flexible than stubs
The primary difference between a mock and a stub is that mocks record and verify interactions between the code under test and the dependencies, whereas stubs only simulate the behavior of dependencies. Mocks are used to ensure that specific interactions occur as expected, while stubs focus on controlling the response of functions or methods.