How do you create HOC using render props?
- By passing a function as a prop to the higher-order component
- By returning a new component from the higher-order component
- By using the withRenderProp() method
- By using the createRenderProp() method
Higher-Order Components (HOCs) are a powerful pattern in React that allow developers to reuse code between components. HOCs can also be implemented using render props, which involves returning a new component from the higher-order component that renders the children using a function prop. This pattern is known as "render prop HOCs" and is a flexible and powerful way to share code between components.
How to create React class components without ES6?
- By using create-react-class method
- By using functional components
- By using the React.Component class directly
The create-react-class method is a way to create React class components without using ES6 syntax. This method allows components to be created using a simple object-based syntax, rather than defining a class and extending the React.Component class. The create-react-class method is useful for creating components that do not require complex logic or state management.
What is the purpose of registerServiceWorker in React?
- To register a new service worker with the browser
- To enable client-side caching of static assets
- To enable offline access to the application
- All of the above
registerServiceWorker is a utility function provided by the Create React App tool that registers a new service worker with the browser. This service worker enables client-side caching of static assets and enables offline access to the application.
What are the lifecycle methods going to be deprecated in React v16?
- componentWillMount and componentWillReceiveProps
- componentWillMount and componentWillUpdate
- componentWillReceiveProps and componentWillUpdate
- componentWillUpdate and componentDidUpdate
The "componentWillReceiveProps" and "componentWillUpdate" lifecycle methods are going to be deprecated in React v16. These methods will be replaced with new lifecycle methods that are more efficient and easier to reason about. The new methods are "getDerivedStateFromProps" and "getSnapshotBeforeUpdate".
How to get history on React Router v4?
- Use the "history" object provided by the "history" module
- Use the "history" object provided by the "react-router-dom" module
- Use the "this.history" object provided by the router
- Use the "this.props.history" object passed to the component
In React Router v4, you can get the history object by using the "this.props.history" object passed to the component. This object contains the current history of the router, including the current location, previous locations, and navigation history. You can use this object to programmatically navigate, access the current URL, or manage the browser history.
How to dispatch an action on load?
- Use a lifecycle method in a component
- Use a middleware
- Dispatch the action in the reducer
To dispatch an action on load, you can use a lifecycle method in a React component, such as componentDidMount(). This method is called once the component has mounted, allowing you to dispatch an action to the Redux store.
How to prevent component from rendering?
- By using the shouldComponentUpdate lifecycle method
- By using the componentDidUpdate lifecycle method
- By using the componentWillMount lifecycle method
- By using the componentWillReceiveProps lifecycle method
In React, components can be prevented from rendering unnecessarily by using the shouldComponentUpdate() lifecycle method. By implementing this method, components can determine whether an update is necessary before rendering. This can help improve performance by minimizing the number of unnecessary re-renders.
What are Redux selectors and why to use them?
- Functions that transform Redux state into a more useful format
- A feature of React that allows you to select DOM elements
- A way to handle asynchronous actions in Redux
- A tool for debugging Redux applications
Redux selectors are functions that transform the Redux state into a more useful format for the application. They allow you to abstract the details of the state shape and provide a simpler interface for accessing and manipulating the state. This helps to keep the code more maintainable and reduces the risk of bugs when the state shape changes.
How to debug forwardRefs in DevTools?
- Use the React Developer Tools to inspect the component hierarchy
- Add console.log statements to the component code
- Use the Chrome DevTools to debug the component code
- Use the React Profiler to analyze component performance
Debugging forwardRefs in React can be challenging, as the ref may not be available in the component code itself. One approach is to use the React Developer Tools to inspect the component hierarchy and check the props and state of each component in the tree. This can help identify any issues with the forwardRef and determine if it is being passed correctly to child components.
What is Lifting State Up in React?
- A technique for managing component state in a centralized location
- A technique for passing data down from parent components to child components
- A technique for passing data up from child components to parent components
- A technique for styling components using CSS-in-JS
Lifting State Up is a technique in React for passing data up from child components to parent components. This is useful when multiple components need to share the same state or when a child component needs to update the state of a parent component.