How can you use TypeScript to ensure a functional component always receives a specific prop?
- Using default prop values.
- Adding comments to the component.
- Wrapping the component in an HTML element.
- Using the "any" type for the prop.
You can use TypeScript to ensure a functional component always receives a specific prop by using default prop values. This way, you specify a default value for the prop, ensuring that the component will receive it even if it's not explicitly provided. Options 2 and 3 are not valid methods for ensuring a specific prop, and option 4 is not recommended as it undermines TypeScript's type checking.
A user frequently visits a media-heavy site on a flaky network. How can you optimize the user experience, ensuring minimal load times on subsequent visits?
- a) Implement client-side rendering for media files.
- b) Use lazy loading for media: Load images and videos only when they come into the viewport.
- c) Increase the size of media files to maintain quality on slow networks.
- d) Disable all media content on the site for users on flaky networks.
To optimize the user experience for a media-heavy site on a flaky network, lazy loading (option b) is the best approach. This technique ensures that images and videos are loaded only when they become visible in the viewport, reducing initial load times. Client-side rendering (option a) may increase load times, larger media files (option c) are counterproductive on slow networks, and disabling all media content (option d) is not a user-friendly solution.
For global state management in a React application, one can use the ________ API.
- Component
- Context
- Render
- State
In React, the "Context" API is used for global state management. It allows you to pass data (state) through the component tree without having to pass props manually at each level. Context provides a way to share data between components at different levels of the hierarchy, making it suitable for global state management in React applications.
You are given a task to optimize a large list rendering in a React application. Which concept would you apply to ensure only changed items are re-rendered?
- Index-based rendering
- Key prop
- Memoization
- Virtual DOM
To optimize large list rendering in React and ensure that only changed items are re-rendered, you should use the key prop. The key prop uniquely identifies each element in the list, allowing React to efficiently update and re-render only the necessary items when the list changes.
Which component is commonly used in React Native to display text on the screen?
- Label
- Paragraph
- String
- Text
In React Native, the common component used to display text on the screen is the "Text" component. It is a fundamental building block for creating user interfaces and rendering text content in a mobile app. React Native developers use the "Text" component to display labels, headings, paragraphs, and other text-based content.
When building a real-time chat application in React, which technology would be most suitable for real-time data updates?
- AJAX
- GraphQL
- REST API
- WebSocket
When building a real-time chat application in React, WebSocket is the most suitable technology for real-time data updates. WebSocket enables full-duplex communication between the client and server, making it ideal for applications that require real-time interactions, such as chat applications. REST API, GraphQL, and AJAX are not designed for real-time updates in the same way WebSocket is.
When you want a component to accept any type of prop but with certain constraints, you can make use of TypeScript's ________.
- any
- generic
- union
- unknown
TypeScript's unknown type is used when you want a component to accept any type of prop but with certain constraints or type checking. It's more restrictive than any as you must perform type assertion or type checking before using values of type unknown. It provides better type safety.
Why might larger applications with a diverse team of developers prefer Redux over the Context API for state management?
- Redux provides a clear structure and guidelines for managing state.
- Redux has better performance with small applications.
- Redux simplifies component communication in a complex app.
- Redux has a smaller learning curve for new developers.
Larger applications with diverse teams often prefer Redux over the Context API because Redux provides a clear structure and guidelines for managing state. This structure helps maintain code quality and consistency across a large codebase, making it easier for team members to collaborate effectively. While the other options may have their merits, they do not address the primary reason for choosing Redux in this context.
For a real-time chat application in React, what pattern can be employed to efficiently manage and display incoming messages?
- Polling
- WebSockets
- Long Polling
- Server-Sent Events (SSE)
To efficiently manage and display incoming messages in a real-time chat application in React, you should employ the WebSockets pattern. WebSockets allow bidirectional communication, enabling the server to push new messages to the client in real-time without the need for constant polling or long polling. While other options like polling and server-sent events are possible, WebSockets are the most efficient choice for real-time applications.
Which pattern in React allows for sharing logic between components without adding component wrappers?
- Component Composition Pattern
- Higher Order Components (HOC)
- Prop Drilling Pattern
- Render Props Pattern
The Render Props Pattern in React allows for sharing logic between components without adding component wrappers. It involves passing a function as a prop to a component, allowing that component to render something based on the logic provided by the function. This pattern promotes code reuse without the need for additional component layers.
In the context of a React application with many components interested in real-time updates, how would you efficiently distribute Websocket messages to relevant components?
- Use a global state management library like Redux or React Context to store and distribute messages.
- Broadcast messages to all components and let them filter the relevant ones.
- Pass messages directly from parent to child components using props.
- Store messages in local component state and handle distribution in each component individually.
To efficiently distribute Websocket messages to relevant components in a React application, it's best to use a global state management library like Redux or React Context (Option 1). This allows you to centralize message handling and ensure that the relevant components receive updates without unnecessary rerendering. The other options are less efficient and may lead to suboptimal performance.
You're building a React application that performs heavy data processing on large datasets. To ensure the UI remains responsive during this processing, which technique should you implement?
- Implementing a single-threaded approach.
- Increasing the UI thread's priority.
- Using asynchronous JavaScript functions (async/await).
- Utilizing Web Workers.
To ensure a responsive UI during heavy data processing, utilizing Web Workers is the recommended approach. Web Workers allow for concurrent execution in the background, preventing the main UI thread from being blocked. Asynchronous JavaScript functions (async/await) are useful but may not fully address UI responsiveness during heavy computations. A single-threaded approach can lead to UI blocking, and increasing the UI thread's priority may not solve the root problem.