When do you need to use refs?
- To access the DOM node of a component
- To pass data between sibling components
- To manage component state
- To update component props
Refs in React are used to access the DOM node of a component. Refs can be attached to any component, including functional components, and allow developers to access the underlying DOM node or React element. Refs are typically used to access the value of an input or textarea element, or to attach event listeners to a DOM node.
What is React Dev Tools?
- A library for managing forms in Redux applications
- A tool for testing React components
- A debugging tool for React applications
- A state management library for React
React Dev Tools is a browser extension and development tool that provides a visual interface for debugging and inspecting the state of a React application. It allows you to track and debug the state and props of your components, as well as inspect the component tree and the performance of your application. React Dev Tools is available for Chrome, Firefox, and other major browsers.
What is the behavior of uncaught errors in React 16?
- They are ignored
- They are logged to the console
- They trigger a fatal error and crash the application
- They trigger an error boundary to catch the error
Uncaught errors in React 16 and later versions trigger a fatal error and crash the application. This behavior was introduced in order to prevent subtle bugs and inconsistencies that could result from errors being silently ignored or logged to the console.
How to access Redux store outside a component?
- Use a global variable
- Use the useContext hook
- Use the useSelector hook
- Use the getState() method
To access the Redux store outside of a component, you can use the getState() method provided by the Redux store. This allows you to access the current state of the store and is often used in middleware or in other parts of the application that do not have direct access to the store.
What is the purpose of using super constructor with props argument?
- To access the parent component's state
- To create a new instance of a component
- To initialize the component's props and state
- To pass props to the parent component
In React, the super() constructor with props argument is used to initialize the component's props and state. It is required when defining a constructor in a class component, and should always be called before accessing this.props or this.state.
What is the difference between React Native and React?
- React Native is a mobile app development framework, while React is a web development framework
- React Native is a JavaScript library, while React is a markup language
- React Native is used for developing web applications, while React is used for developing mobile applications
- React Native and React are the same thing
React Native is a mobile app development framework that allows developers to build mobile applications using JavaScript and React. It is a separate technology from React, which is a JavaScript library for building user interfaces on the web. While both React and React Native use a similar programming model, they have different APIs and are optimized for different platforms.
What is Flux?
- A testing framework for React
- A database management system
- A design pattern for managing state in React applications
- A CSS preprocessor
Flux is a design pattern for managing state in React applications. It was developed by Facebook and is often used in combination with React. Flux emphasizes a unidirectional data flow, in which data flows in a single direction through the application. This helps prevent issues with data inconsistency and makes it easier to manage state in large applications.
Why React tab is not showing up in DevTools?
- The React DevTools extension is not installed
- The React app is not running in development mode
- There is a conflict with other browser extensions
- The React app is not using React version 16 or higher
If the React tab is not showing up in DevTools, it may be because the React app is not using React version 16 or higher. The React tab was introduced in version 16, so if you are using an earlier version of React, it will not be available in DevTools. You can check the React version in your app by looking at the package.json file or by running the command 'npm ls react'.
How to do logging in React Native?
- Use the console.log() function
- Use the alert() function
- Use the debugger statement
- All of the above
To do logging in React Native, you can use the console.log() function, which writes messages to the console in the same way as in a web browser. You can also use other console functions, such as console.warn() and console.error(), to log warning and error messages.
What is context?
- A JavaScript library for data visualization
- A global object used to store application state
- A way to pass data down to child components without using props
- A way to pass data up to parent components without using props
Context is a way to pass data down to child components without using props. It is useful for data that needs to be accessed by many components at different levels of the component hierarchy. Context provides a way to avoid the "prop drilling" problem, where props need to be passed down through many layers of components.
How do you access the imperative API of web components?
- Use the refs API in React
- Use the useEffect() hook in React
- Use the setState() method in React
- Use the createContext() API in React
In React, you can use the refs API to access the imperative API of web components. By using refs, you can reference a web component and then access its imperative API methods and properties.
How to reset state in Redux?
- Dispatch a RESET action
- Modify the state directly
- Use the combineReducers function
To reset the state in Redux, you can dispatch a RESET action to the Redux store. This action can be handled by a reducer function that returns the initial state of the application. This allows you to reset the application state to its initial values.