You are tasked with visualizing large datasets in a dashboard application with the capability of drilling down data. Which type of UI integration would be the most suitable?
- Audio integration (e.g., Spotify)
- Data visualization libraries (e.g., D3.js)
- Gaming integration (e.g., Unity)
- Video integration (e.g., YouTube)
For visualizing large datasets and creating interactive dashboards with drill-down capabilities, data visualization libraries like D3.js are the most suitable choice. D3.js allows you to create custom and dynamic data visualizations that can handle complex data interactions. Audio, video, and gaming integrations are unrelated to data visualization and would not serve this purpose.
Which of the following is a method to update state in class components in React?
- this.setState({})
- useState()
- updateState()
- this.state = {}
In class components in React, you can update state using the this.setState({}) method. This method allows you to modify the component's state and triggers a re-render. The other options are not valid ways to update state in class components. useState() is used in functional components, updateState() is not a built-in method, and directly modifying this.state is discouraged.
When making API calls in a React component, what is a common side effect that needs to be handled?
- Defining component lifecycle methods.
- Handling asynchronous operations.
- Managing component state changes.
- Styling component elements.
When making API calls in a React component, handling asynchronous operations is a common side effect. This is because API calls are typically asynchronous, and it's important to ensure that the component can manage these operations effectively without causing blocking or errors. While managing component state is crucial in React, it's not specific to API calls. The use of lifecycle methods and styling are also important but not specific to API calls.
Which of the following scenarios is NOT ideally suited for a HOC?
- Managing global application state.
- Implementing user authentication.
- Adding local state to a single component.
- Logging user interactions.
Higher Order Components (HOCs) are typically used for cross-cutting concerns like user authentication, logging, and managing global application state. However, adding local state to a single component is not ideally suited for a HOC. Local component state can be managed within the component itself without the need for a HOC. Therefore, option 3 is not the ideal scenario for HOC usage.
You're building a form in React. Users report that when they press "Enter", the page refreshes. What should you do to prevent this default behavior?
- Use event.preventDefault() in the form's onSubmit handler.
- Change the form to a
element.
- Set the target attribute of the form to _self.
- Add a window.preventRefreshOnEnter = true statement.
To prevent the default behavior of page refresh when users press "Enter" in a form in React, you should use event.preventDefault() within the form's onSubmit handler. This code prevents the browser's default form submission behavior, ensuring that the page does not refresh upon pressing "Enter." The other options are not appropriate solutions to this problem.
Which of the following hooks is used to manage local state in functional components?
- componentDidMount
- this.state
- useEffect
- useState
useState is the React hook used to manage local state in functional components. It allows functional components to maintain their state without using class components. useEffect is used for side effects and lifecycle methods like componentDidMount are used in class components, not functional ones. this.state is used in class components but not with hooks.
Which of the following is a typical use case for using Render Props in React applications?
- Code sharing between unrelated components.
- Component styling with CSS.
- Data fetching and state management.
- Routing in React applications.
Render Props are often used for data fetching and state management in React applications. They allow components to provide data or functionality to their children, making them a suitable choice for scenarios where components need to share data or behavior without being tightly coupled. They are not typically used for unrelated code sharing, styling, or routing.
For a large application, what strategy can be applied in Webpack to efficiently split and load code chunks?
- Code splitting using dynamic imports and Webpack's built-in SplitChunksPlugin.
- Concatenating all code into a single bundle for faster loading.
- Minifying all JavaScript files into a single bundle.
- Using external CDN links for all JavaScript files.
In a large application, code splitting using dynamic imports and Webpack's built-in SplitChunksPlugin is a common strategy to efficiently split and load code chunks. This allows for better management of dependencies and loading only the necessary code for each page, resulting in faster initial load times and better performance. It's an essential technique for optimizing large-scale applications in a DevOps context.
In the context of React Router, what is the difference between exact and strict when defining a Route?
- exact ensures that the route matches exactly with the path, including trailing slashes.
- strict ensures that the route matches exactly with the path, ignoring trailing slashes.
- exact matches the route case-insensitively, while strict matches it case-sensitively.
- strict is used to define routes that are only accessible when a user is logged in.
In React Router, the difference between exact and strict when defining a Route is that exact ensures that the route matches exactly with the path, ignoring trailing slashes, while strict ensures that the route matches exactly with the path, including trailing slashes. This is useful for handling route matching with or without trailing slashes. The other options are not accurate descriptions of exact and strict in the context of React Router.
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'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.
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.