1.
What is React?
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Xamarin React interview questions.
Only challenges
- 2.
How does React work under the hood?
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- 3.
What are some key advantages of building UIs with React?
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- 4.
What are some potential limitations or disadvantages of React?
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- 5.
What is JSX?
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- 6.
What is state in React?
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- 7.
What is the difference between state and props ?
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- 8.
What are React Hooks?
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- 9.
What benefits do React Hooks provide over class components ?
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- 10.
Can you show an example of a simple custom React Hook and why they are useful?
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- 11.
What are refs used for in React?
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- 12.
Why pass props to the super() constructor in React classes ?
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- 13.
How can you apply inline styling in React?
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- 14.
How do Class and Functional components differ in React?
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- 15.
How do Presentational and Container components differ in React?
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- 16.
What are Higher-Order Components in React and how are they useful?
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- 17.
What does it mean for a React component to be mounted ?
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- 18.
Walk through what happens when you call setState() in React
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- 19.
Why pass a callback function to setState() in React?
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- 20.
How does the useState() hook work in React?
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- 21.
What is the purpose of the Context API in ReactJS and when is it useful?
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- 22.
What problem do Fragments solve in React?
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- 23.
How can you ensure a function runs only once with useEffect() in React?
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- 24.
What role do props play in React components?
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- 25.
When and why are refs useful in React?
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- 26.
What's the difference between a Controlled component and an Uncontrolled one in React?
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- 27.
When rendering a list what is a key and what is its purpose?
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- 28.
What is the typical way to create and use refs in React?
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- 29.
What are some characteristics of Stateful components in React?
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- 30.
What are some characteristics of Stateless components in React?
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- 31.
What problem do portals solve in React and when would you use them?
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- 32.
How are Components and Containers different in Redux?
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- 33.
How can you use inline conditional expressions in ReactJS?
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- 34.
What is the Reconciliation process in ReactJS?
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- 35.
How are Elements and Components different in ReactJS?
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- 36.
What are some ways to access DOM elements in React?
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- 37.
What are the main phases in the React component lifecycle ?
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- 38.
Why is directly modifying state a bad idea in React?
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- 39.
Why are keys useful and how should they be used when rendering lists in React?
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- 40.
What is Component Composition in React and why is it useful?
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- 41.
How are useState() and useReducer() different in React?
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- 42.
Are there any limitations of React Hooks compared to classes?
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- 43.
How do Pure Components in React improve performance?
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- 44.
What problem do Error Boundaries solve in React?
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- 45.
How does StrictMode help when developing React apps?
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- 46.
How can shouldComponentUpdate() improve React performance?
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- 47.
Can you explain the Flux pattern and how it relates to React?
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- 48.
What does the {this.props.children} prop allow you to do in React?
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- 49.
How can you prevent a React component from unnecessary rendering ?
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- 50.
What is the typical way to render a list of components from an array in React?
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- 51.
What does the typical data flow look like in a React + Redux app?
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- 52.
What are some limitations on what you should do inside the component render method in React?
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- 53.
What are some ways to correctly bind event handlers in React classes?
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- 54.
What is prop drilling and how can you avoid it in React?
Answer:
- 55.
What is the purpose of shouldComponentUpdate() in React?
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- 56.
How do forward refs work in React?
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- 57.
What does the spread syntax (...) do in React?
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- 58.
How are Shadow DOM and Virtual DOM different in React?
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- 59.
Why bind class methods and event handlers to this in React classes?
Answer:
- 60.
What are some benefits of using Stateless Functional Components in React?
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- 61.
Why does React use className instead of the HTML class attribute?
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- 62.
What does Lifting State Up mean in React?
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- 63.
How are useRef() and createRef() different in React?
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- 64.
What's the difference between React.createElement() and React.cloneElement() ?
Answer:
- 65.
What common mistake leads to functions being called incorrectly on each render?
Answer:
- 66.
How does React event handling differ from native HTML events ?
Answer:
- 67.
What are some downsides of using React Context ?
Answer:
- 68.
What does Batching mean in React and how does it improve performance?
Answer:
- 69.
Which class component lifecycle methods can be replaced by useEffect() ?
Answer:
- 70.
What are some ways to handle errors with Error Boundaries in function components?
Answer:
- 71.
When is it useful to use the useRef() hook in React?
Answer:
- 72.
What are some ways to pass data from child to parent in React?
Answer:
- 73.
What is the optional second callback argument that can be passed to setState() ?
Answer:
- 74.
How would you manually create this JSX element without using JSX ?
Answer:
- 75.
Can you spot two potential issues with the React component code shown?
Answer:
- 76.
How to rewrite this React class component code using hooks instead?
Answer:
- 77.
What might be problematic about handling state like this in React?
Answer:
- 78.
How does component initialization differ between constructor() and getInitialState() in React?
Answer:
- 79.
What are some ways to validate props in React components?
Answer:
- 80.
What are the key differences between Flux and MVC patterns?
Answer:
- 81.
Is it possible to force a component to re-render without setState() in React?
Answer:
- 82.
Why does React use Synthetic Events ?
Answer:
- 83.
How would you debug performance issues with slow component rendering in React?
Answer:
- 84.
What makes a component a Pure Functional one in React?
Answer:
- 85.
Why is it important to pass props to the super() constructor in React classes?
Answer:
- 86.
Why bind event handlers to this in React class components?
Answer:
- 87.
Why doesn't this.props.children.map() work as expected in React?
Answer:
- 88.
How could you create a Props Proxy in a React higher order component?
Answer:
- 89.
What are some ways to conditionally render attributes in React components?
Answer:
- 90.
Does React re-render all components when setState() is called?
Answer:
- 91.
How does React handle events differently than regular DOM events ?
Answer:
- 92.
In what cases might you use the StrictMode component in React?
Answer:
- 93.
When should you use useCallback() , useMemo() and useEffect() in React components?
Answer:
- 94.
Is true inheritance possible between components in React?
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- 95.
How do Incremental DOM and Virtual DOM differ in React?
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- 96.
When might you need to use ReactDOM.flushSync() ?
Answer:
- 97.
When is the useReducer() hook useful in React?
Answer:
- 98.
How to store non-reactive state in React function components?
Answer:
- 99.
If you rendered a Twitter React element like below, how might the Twitter component be implemented?
Answer:
- 100.
Is there anything potentially wrong or suboptimal about this use of React's setState() ?
Answer:
- 101.
How can you prevent multiple re-renders when using several useState() hooks?
Answer:
- 102.
How does React as a UI library differ from Angular as a framework ?
Answer:
- 103.
What are some differences between Flux and AngularJS approaches?
Answer:
- 104.
What does React Fiber aim to improve?
Answer:
- 105.
How can you avoid the need for binding in React class components?
Answer:
- 106.
How and why would you use React.memo() ?
Answer:
- 107.
Is it a good idea for custom React hooks to return JSX ?
Answer:
- 108.
What is the order of execution of useInsertionEffect() , useEffect() , and useLayoutEffect() ?
Answer:
- 109.
How could you optimize this component with slow list filtering using a React Hook ?
Answer:
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