________ tools are crucial in analyzing and removing unused code through tree shaking.
- Babel
- Linter
- Bundler
- Minifier
Bundlers play a key role in tree shaking. They are responsible for analyzing the dependencies between modules, identifying unused code, and removing it during the build process. Common bundlers like Webpack and Rollup are often configured to perform tree shaking to optimize the final bundle size.
What are the limitations of using the spread operator for deep cloning complex objects?
- It does not handle circular references well.
- It only works for primitive data types.
- It cannot clone objects with prototype chains.
- It cannot clone functions.
The spread operator is limited in deep cloning when dealing with circular references, making it less suitable for complex object structures. Circular references can result in infinite loops during cloning.
Which of the following is not a state of a Promise?
- Completed
- Fulfilled
- Rejected
- Pending
"Completed" is not a standard state of a Promise. The valid states are "Pending," "Fulfilled," and "Rejected." A Promise is initially in the "Pending" state and transitions to either "Fulfilled" or "Rejected" based on the outcome of the asynchronous operation it represents.
For an analytics dashboard that requires data transformation, how would higher-order functions streamline this process?
- map
- reduce
- filter
- forEach
The correct option is map. map is used for transforming each element of an array and creating a new array with the transformed values. It is ideal for data transformation tasks in scenarios like an analytics dashboard.
Consider a web application where you need to apply multiple transformations to user input. How would functional composition enhance this process?
- Improved Reusability and Modularity
- Increased Complexity and Maintenance
- Streamlined Debugging and Error Handling
- Reduced Code Duplication and Enhanced Readability
Functional composition allows breaking down complex transformations into smaller, reusable functions. This promotes code modularity, simplifies debugging, and enhances readability by reducing code duplication. It streamlines the development process by composing functions to perform various transformations efficiently. This approach leads to more maintainable and scalable code.
How can destructuring assignment be effectively used in React components to handle props and state?
- It cannot be used with React components
- It simplifies access to props and state values
- It makes React components slower
- It is only applicable to class components
Destructuring assignment is commonly used in React components to handle props and state efficiently. By extracting specific values from the props and state objects using destructuring syntax, developers can improve code readability and make component logic more concise. This practice simplifies the process of accessing and using props and state values within the component, contributing to better-organized and more maintainable React code.
How do enhanced object literals in ES6 facilitate the assignment of variables as properties of objects?
- Dynamic Assignment
- Property Binding
- Object Linking
- Variable Embedding
In ES6, enhanced object literals allow dynamic assignment of variables as properties using square brackets. This feature is especially useful when the property name needs to be determined at runtime. It promotes a more flexible and concise way of defining object properties.
To export multiple features from a single module, use export { feature1, feature2 as _______ };.
- alias
- as
- export
- feature2
To export multiple features from a single module, use export { feature1, feature2 as alias }; where as alias provides an optional alias for the exported feature, making it clear when imported.
Consider a scenario where you are managing a list of items in a shopping cart. Would you use let or const to declare the list, and why?
- Use let
- Use const
- Either let or const, depending on the use case
- It doesn't matter, both let and const work the same way
In this scenario, you would use const to declare the list because the shopping cart items should not be re-assigned. This enhances code safety and prevents accidental modifications.
Which array method would you use to transform an array into a single value?
- reduce
- filter
- forEach
- map
The reduce method is used to transform an array into a single value by applying a function that accumulates the values of the array. It takes a callback function and an initial value, and iterates over the array, updating the accumulator with the result of the callback function. This is commonly used for summing up values or performing other aggregations.