Components that manage and maintain their own state are referred to as ________ components.
- controlled
- functional
- stateless
- uncontrolled
Components that manage and maintain their own state are referred to as stateful components. These components hold their own state data and are responsible for rendering and updating it. Stateless components, on the other hand, do not manage their own state and rely on props passed to them.
You're developing an e-commerce app and want to lazily load product details only when a user clicks on a product. Which React feature would you leverage?
- React Context
- React Hooks useEffect()
- React Router Route component
- React Suspense
To lazily load product details in a React app, you would typically leverage the React Suspense feature in combination with React.lazy(). Suspense allows you to specify loading behavior for components, and React.lazy() lets you load components lazily, which is suitable for this scenario. useEffect() is used for managing side effects, Route is for routing, and Context is for state management, not specifically for lazy loading.
How do you bind an event handler in the constructor of a React class component?
- Using arrow functions: this.handleEvent = this.handleEvent.bind(this);
- By assigning it directly: this.handleEvent = this.handleEvent.bind(this);
- Using the super() method: super.handleEvent = this.handleEvent.bind(this);
- It's not necessary to bind event handlers in the constructor of a class component in React.
In React, you typically bind an event handler in the constructor using an arrow function, as shown in option 1. This is done to ensure that the value of this within the event handler refers to the component instance. While option 2 is also correct, it's not the recommended way. Option 3 is incorrect, and option 4 is not accurate, as binding is often necessary to avoid issues with the value of this.
You are building a React application that needs to work offline. Which technology would you leverage to allow the app to function without an internet connection?
- GraphQL
- REST APIs
- Service Workers
- WebSockets
To make a React application work offline, you would leverage Service Workers. Service Workers enable caching of assets and allow the app to function without an internet connection by serving cached content when offline. WebSockets, REST APIs, and GraphQL are not primarily designed for offline functionality but rather for real-time communication and data retrieval.
What is a potential downside or limitation of the current React diffing algorithm?
- It can lead to excessive virtual DOM updates in some cases.
- It cannot handle component state changes effectively.
- It is not compatible with modern JavaScript features.
- It relies too heavily on manual key assignments.
One potential downside of the current React diffing algorithm is that it can lead to excessive virtual DOM updates in some cases. If component updates are frequent or the tree structure is complex, React may perform more updates than necessary, affecting performance. Developers need to be mindful of optimizing their components and key assignments to mitigate this limitation and improve React app performance.
Stateless components in React are also known as ________ components.
- Pure Components
- Functional Components
- Dynamic Components
- Class Components
Stateless components in React are also known as Functional Components. These components are defined as JavaScript functions and do not have internal state management. They receive props and render content based on those props. The other options do not accurately describe stateless components.
One common use case for using React Portals is rendering modals outside the main application DOM hierarchy.
- Dropdowns
- Modals
- Popovers
- Portals
React Portals are commonly used to render modals outside the main DOM hierarchy. This is especially useful for rendering elements like modals, which need to float above the main application content but may have complex structures.
To connect a React component to the Redux store, one commonly uses the ________ function.
- connectToRedux
- mapStateToProps
- mapStoreToComponent
- reactStoreConnector
To connect a React component to the Redux store, one commonly uses the mapStateToProps function. This function maps the state from the Redux store to the props of the connected component, allowing it to access and display the state data. It's an essential part of integrating Redux with React for state management.
How would you handle errors when making an API call using Axios?
- By returning an empty response on error.
- By setting the error status code to 404.
- By throwing an exception on error.
- By using the catch() method for error handling.
When making API calls using Axios, you can handle errors by using the catch() method to catch any errors that occur during the request. Axios will reject the promise if the request encounters an error, allowing you to handle the error condition and take appropriate actions. Throwing an exception or returning an empty response are not standard error-handling practices in Axios.
While splitting code with Webpack, you notice that two routes share a significant amount of code. How can you ensure that the shared code is not loaded multiple times for users?
- Combine the code for both routes into a single file.
- Implement server-side rendering to avoid code duplication.
- Load the shared code using a CDN for faster delivery.
- Use Webpack's code splitting with dynamic imports to create a shared bundle.
To prevent shared code from being loaded multiple times, you should use Webpack's code splitting with dynamic imports to create a shared bundle. This ensures that the shared code is loaded once and reused across routes as needed. Combining code into a single file doesn't achieve code separation and may result in larger bundles. Loading via CDN and server-side rendering address different issues.