What is React-Intl?

  • A library for internationalization in React
  • A library for managing state in React
  • A library for styling React components
  • A library for testing React components
React-Intl is a library for internationalization (i18n) in React applications. It provides a set of components, utilities, and formatting functions to handle different languages, locales, and cultural conventions. With React-Intl, you can easily translate text, format dates and numbers, and manage pluralization and gender.

What are the exceptions on React component naming?

  • All the options
  • Components can include numbers, but not as the first character
  • Components must be named with camelCase convention
  • Components must start with a capital letter
In React, there are several rules for naming components, including that components must start with a capital letter, use camelCase convention, and can include numbers, but not as the first character. Components should also have a descriptive name that reflects their purpose or function in the application.

What is the recommended ordering of methods in component class?

  • Constructor, event handlers, render, lifecycle methods
  • Constructor, render, lifecycle methods, event handlers
  • Lifecycle methods, constructor, render, event handlers
  • Render, constructor, lifecycle methods, event handlers
The recommended ordering of methods in a React component class is as follows: constructor, render, lifecycle methods, event handlers. This ordering groups related methods together and makes it easier to understand and maintain the code.

How to programmatically trigger click event in React?

  • Use the "document.dispatchEvent" method with a custom event
  • Use the "onClick" attribute with a function call
  • Use the "simulate" method in the "react-test-renderer" package
  • Use the "trigger" method in the "react-click-events" library
In React, you can programmatically trigger a click event by using the "simulate()" method in the "react-test-renderer" package. This method allows you to simulate a click event on a React component, and can be useful for testing or automation purposes. For example: TestRenderer.act(() => { buttonInstance.simulate('click'); });.

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.

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 TestRenderer package in React?

  • A package for mocking HTTP requests
  • A package for generating test data
  • A tool for simulating component rendering without deep rendering
  • A tool for rendering React components to JSON format
TestRenderer is a package that allows developers to render React components to a JSON format, making it easier to test and debug components. It is used for snapshot testing and is similar to the ReactTestUtils package.

What is Concurrent Rendering?

  • A rendering technique for low-end devices
  • A rendering technique for high-end devices
  • A new feature in React 18
  • A way to render multiple parts of a component tree at the same time
Concurrent Rendering is a new rendering strategy introduced in React 18 that allows multiple parts of a component tree to be rendered at the same time, without blocking the UI thread. This means that the user interface can remain responsive while React is rendering updates. Concurrent Rendering is particularly useful for large and complex applications that need to maintain high performance.

How to pass a parameter to an event handler or callback?

  • Using an arrow function
  • Using the bind method
  • Using the event object
  • Using the setState method
A parameter can be passed to an event handler or callback in React by using an arrow function. The arrow function takes the event as a parameter, along with any additional parameters that need to be passed. This approach ensures that the event object is properly handled and that the correct parameters are passed to the event handler or callback.

How to update a component every second?

  • Use the setInterval() function in the componentDidMount() method
  • Use the setInterval() function in the constructor method
  • Use the setTimeout() function in the componentDidUpdate() method
  • Use the setTimeout() function in the render() method
In React, you can update a component every second by using the "setInterval()" function in the "componentDidMount()" lifecycle method. This will create a timer that updates the component state every second, causing the component to re-render with the new state values. For example: componentDidMount() { this.timerID = setInterval(() => this.tick(), 1000); }.