__________ can be used to execute a callback on every element in the array, creating a new array with the results.
- map
- forEach
- reduce
- filter
The forEach method can be used to execute a callback function on each element of an array. However, it doesn't create a new array with the results.
Generator functions can be used to implement _________ programming patterns, like handling asynchronous operations in a synchronous manner.
- Synchronous
- Asynchronous
- Parallel
- Concurrent
Generator functions in JavaScript can be used to implement asynchronous programming patterns. By yielding promises and using async/await syntax, asynchronous operations can be handled in a more synchronous-looking manner, enhancing code readability and maintainability.
What is the benefit of using tree shaking with ES6 modules?
- Eliminates dead code and reduces bundle size
- Improves module readability and organization
- Enhances runtime performance through JIT compilation
- Enables better debugging with source maps
Tree shaking is a technique in which unused or dead code is eliminated during the bundling process. It helps reduce the final bundle size, resulting in faster loading times and improved performance.
When building a localization library, how could template literals be used to manage dynamic content?
- They allow for easy integration of variables representing language-specific content.
- They simplify the translation process by providing a concise syntax for language keys.
- They enable the dynamic loading of language-specific templates at runtime.
- They automatically detect the user's language and adjust the content accordingly.
Template literals are valuable in localization by facilitating the integration of variables for dynamic content in different languages.
Unlike callbacks, Promises support _______ chaining, which helps in writing cleaner code.
- callback
- asynchronous
- promise
- then
The correct option is 'then.' Promises support 'then' chaining, allowing you to chain multiple asynchronous operations in a more readable and maintainable way. This is a significant improvement over callbacks, leading to cleaner and more structured code.
When chaining promises, the return value of one .then() becomes the input for the next _________.
- catch()
- resolve()
- reject()
- then()
The correct term is then(). When chaining promises, the then() method is used to specify what should happen next after the Promise is fulfilled. The value returned by the then() callback becomes the input for the next then() in the chain.
When using const with destructuring, you must provide a _________ at the time of declaration.
- Value
- Reference
- Type
- Default Value
When using const with destructuring, you must provide a value at the time of declaration. This is because, once a variable is declared with const, you cannot reassign it later.
Can await be used inside a regular (non-async) function?
- No, it can only be used in async functions
- Yes, it can be used to make any function asynchronous
- Yes, but it will result in a runtime error
- No, it is only applicable in arrow functions
The await keyword can only be used inside functions marked with the async keyword. Attempting to use await in a regular function will result in a syntax error.
In ES6, which scenario would necessitate using let over const?
- When the variable needs to be reassigned
- When the variable should remain constant throughout its scope
- When the variable is used in a loop
- When the variable is a function declaration
The 'let' keyword should be used when the variable needs to be reassigned within its scope, as 'const' variables cannot be reassigned after initialization. 'const' is appropriate for variables that should remain constant throughout their scope.
When implementing a function to make API requests, how would you structure it to effectively handle both network errors and incorrect responses?
- Returning an error object for network errors and throwing an exception for incorrect responses
- Using separate callback functions for network errors and incorrect responses
- Combining network errors and incorrect responses into a single error object
- Utilizing a single callback function with different error codes for network and response issues
By returning an error object for network errors and throwing an exception for incorrect responses, the function can communicate distinct issues. This approach ensures a clear separation between network-related errors and issues with the API response, allowing for better identification and handling of specific problems. Separate callback functions or combining errors into a single object may lead to ambiguity in error handling.