250+ React Js MCQ With Online Practice Test

React.js, often simply called React, is a highly popular JavaScript library for building user interfaces. Developed and maintained by Facebook, React is renowned for its component-based architecture and the ability to efficiently update and render components when data changes. It is a foundational tool for developing modern web and mobile applications, allowing developers to create dynamic and interactive user interfaces with ease. React's vast ecosystem, including tools like React Native for mobile app development, makes it a top choice for frontend development and a key player in the world of web technologies.

Practice Test

131. What is the primary way to style React components?

Answer: Inline styles

132. In React, how can you apply inline styles to components using JavaScript objects?

Answer: By using the style attribute

133. Which CSS-in-JS library is commonly used for styling React components?

Answer: Styled Components

134. In React, why is it beneficial to use a CSS-in-JS library like Styled Components?

Answer: To reduce the size of the bundle

135. What is the advantage of using external CSS files for styling React components?

Answer: Easy reusability and separation of concerns

136. In React, how do you add CSS classes to components using JSX?

Answer: By using the className attribute

137. When using Styled Components in React, how are styles defined for a component?

Answer: As tagged template literals

138. What is a potential drawback of using inline styles in React components?

Answer: Limited support for dynamic styling

139. Which CSS preprocessor is often used in combination with React for enhanced styling capabilities?

Answer: Sass

140. In React, how do you conditionally apply styles to components based on component state or props?

Answer: By using conditional statements
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React Js Multiple Choice Questions React Js MCQ React Js Interview Questions With Answers