How to use class field declarations syntax in React classes?
- Use the constructor method
- Use the componentWillMount lifecycle method
- Use the componentDidMount lifecycle method
- Use the class fields syntax
The class fields syntax can be used to declare class properties directly on the class without the need for a constructor method. This syntax can be used in React classes to declare state and other properties.
How do you say that props are read-only?
- By using Object.freeze()
- By using Object.preventExtensions()
- By using Object.seal()
- By not modifying them directly
In React, props are read-only and should not be modified directly. Attempting to modify props directly can cause bugs and make components unpredictable. Instead, components should create and maintain their own state to manage changes to data.
What's the purpose of at symbol in the redux connect decorator?
- It is used to reference a component's props
- It is used to reference the Redux store's state
- It is used to reference a component's state
The @ symbol in the Redux connect decorator is used to reference the state of the Redux store. This allows the component to access the store's state without having to pass it down as props.
Why fragments are better than container divs?
- Fragments are easier to use
- Fragments are more performant
- Fragments are more semantic
- Fragments are not better than container divs
Fragments are better than container divs because they are more performant. Using a container div adds an extra DOM node, which can slow down rendering and create problems with styling. Fragments, on the other hand, allow you to group elements without adding any extra nodes to the DOM.
How to fetch data with React Hooks?
- Use the componentDidMount() method
- Use the fetch() function in a useEffect() hook
- Use the componentWillMount() method
- Use the AJAX library
In React, you can use the useEffect() hook to fetch data from an API. Inside the useEffect() hook, you can use the fetch() function to make a request to the API and update the component state with the response data.
What is the diffing algorithm?
- A process for comparing two React elements
- A process for reconciling changes in the React component tree
- A process for optimizing React component rendering
- A process for testing React components
The diffing algorithm is the process used by React to reconcile changes in the component tree and update the DOM. The diffing algorithm compares the new tree of React elements with the previous tree and identifies the minimum set of changes needed to update the DOM. This process is also known as reconciliation and is a key part of React's performance optimizations.
Can Redux only be used with React?
- Yes, Redux can only be used with React
- No, Redux can be used with any JavaScript framework or library
No, Redux can be used with any JavaScript framework or library, not just React. Redux is a standalone state management library that can be used with any UI framework or library, as well as with vanilla JavaScript applications. While it is commonly used with React, it can also be used with other popular frameworks such as Angular, Vue.js, and Ember.
What is the main purpose of constructor?
- To initialize the component's state and bind methods to the component
- To define the component's markup and styling
- To render the component's children
- To handle events and update the component's state
The main purpose of the constructor in a React component is to initialize the component's state and bind methods to the component. The constructor is called before the component is mounted and can be used to set the initial state of the component or to bind methods to the component.
How to use font-awesome icons in React?
- Use the Font Awesome component library for React
- Import the Font Awesome CSS file and use the class names
- Use the React Native vector icons library
- There is no way to use Font Awesome icons in React
To use Font Awesome icons in React, you can use the Font Awesome component library for React. This library provides a set of pre-built components for rendering Font Awesome icons, which you can use in your React applications. Alternatively, you can import the Font Awesome CSS file and use the class names directly in your components.
Can you describe the componentDidCatch lifecycle method signature?
- componentDidCatch(error: Error, errorInfo: object)
- componentDidCatch(error: string, errorInfo: object)
- componentDidCatch(error: Error, errorInfo: string)
- componentDidCatch(error: string, errorInfo: string)
The componentDidCatch lifecycle method is called whenever an error is thrown in a component's child tree. The method has a signature of componentDidCatch(error: Error, errorInfo: object). The error parameter is the actual error object that was thrown, while the errorInfo parameter is an object that contains additional information about the error, such as the component stack trace.