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Which of the following lifecycle methods is called only once, after the initial render?
- a) componentWillMount
- b) componentDidMount (Correct Answer)
- c) componentDidUpdate
- d) componentWillUnmount
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In React, what is the purpose of the key prop when rendering a list of components?
- a) It defines the style of each list item
- b) It helps React identify which items have changed, are added, or are removed in the list (Correct Answer)
- c) It sets the initial state of each list item
- d) It specifies the order of the list items
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Which hook is used for memoizing the result of a function so that it is only recomputed when its dependencies change?
- a) useMemo (Correct Answer)
- b) useCallback
- c) useEffect
- d) useRef
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What is the purpose of the shouldComponentUpdate method in React?
- a) To fetch data from an API before the component updates
- b) To determine if a component should re-render by returning true or false (Correct Answer)
- c) To update the component's state
- d) To perform side effects after the component updates
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In React, what is the recommended way to handle forms?
- a) Using regular HTML form elements
- b) Using controlled components where form data is handled by React state (Correct Answer)
- c) Using uncontrolled components where form data is handled by the DOM
- d) Using Redux for form state management
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Which of the following is NOT a valid use case for React context?
- a) Theme management
- b) Localization
- c) Managing application-wide state (Correct Answer)
- d) Passing props between deeply nested components
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What is the purpose of the setState function in React?
- a) To update the component's state (Correct Answer)
- b) To define the initial state of a component
- c) To fetch data from an API
- d) To subscribe to context changes
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Which hook is used to perform side effects in functional components?
- a) useState
- b) useEffect (Correct Answer)
- c) useContext
- d) useReducer
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In React, how can you conditionally render components?
- a) By using the if-else statement inside the render method
- b) By using ternary operators inside JSX (Correct Answer)
- c) By using switch statements inside JSX
- d) By using the renderIf function
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Which of the following is a benefit of using React JS?
- a) Improved performance due to the use of virtual DOM
- b) Reusability of components
- c) Easy integration with other libraries and frameworks
- d) All of the above (Correct Answer)
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