React Interview Questions & Answers

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Note: This repository is specific to ReactJS. Please check Javascript Interview questions for core javascript questions and DataStructures and Algorithms for DSA related questions or problems.

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No.	Questions
	Core React
1	What is React?
2	What is the history behind React evolution?
3	What are the major features of React?
4	What is JSX?
5	What is the difference between Element and Component?
6	How to create components in React?
7	When to use a Class Component over a Function Component?
8	What are Pure Components?
9	What is state in React?
10	What are props in React?
11	What is the difference between state and props?
12	What is the difference between HTML and React event handling?
13	What are synthetic events in React?
14	What are inline conditional expressions?
15	What is "key" prop and what is the benefit of using it in arrays of elements?
16	What is Virtual DOM?
17	How Virtual DOM works?
18	What is the difference between Shadow DOM and Virtual DOM?
19	What is React Fiber?
20	What is the main goal of React Fiber?
21	What are controlled components?
22	What are uncontrolled components?
23	What is the difference between createElement and cloneElement?
24	What is Lifting State Up in React?
25	What are Higher-Order components?
26	What is children prop?
27	How to write comments in React?
28	What is reconciliation?
29	Does the lazy function support named exports?
30	Why React uses className over class attribute?
31	What are fragments?
32	Why fragments are better than container divs?
33	What are portals in React?
34	What are stateless components?
35	What are stateful components?
36	How to apply validation on props in React?
37	What are the advantages of React?
38	What are the limitations of React?
39	What are the recommended ways for static type checking?
40	What is the use of react-dom package?
41	What is ReactDOMServer?
42	How to use InnerHtml in React?
43	How to use styles in React?
44	How events are different in React?
45	What is the impact of indexes as keys?
46	How do you conditionally render components?
47	Why we need to be careful when spreading props on DOM elements??
48	How do you memoize a component?
49	How you implement Server-Side Rendering or SSR?
50	How to enable production mode in React?
51	Do Hooks replace render props and higher order components?
52	What is a switching component?
53	What are React Mixins?
54	What are the Pointer Events supported in React?
55	Why should component names start with capital letter?
56	Are custom DOM attributes supported in React v16?
57	How to loop inside JSX?
58	How do you access props in attribute quotes?
59	What is React PropType array with shape?
60	How to conditionally apply class attributes?
61	What is the difference between React and ReactDOM?
62	Why ReactDOM is separated from React?
63	How to use React label element?
64	How to combine multiple inline style objects?
65	How to re-render the view when the browser is resized?
66	How to pretty print JSON with React?
67	Why you can't update props in React?
68	How to focus an input element on page load?
69	How can we find the version of React at runtime in the browser?
70	How to add Google Analytics for react-router?
71	How do you apply vendor prefixes to inline styles in React?
72	How to import and export components using react and ES6?
73	What are the exceptions on React component naming?
74	Is it possible to use async/await in plain React?
75	What are the common folder structures for React?
76	What are the popular packages for animation?
77	What is the benefit of styles modules?
78	What are the popular React-specific linters?
	React Router
79	What is React Router?
80	How React Router is different from history library?
81	What are the <Router> components of React Router v6?
82	What is the purpose of push and replace methods of history?
83	How do you programmatically navigate using React router v4?
84	How to get query parameters in React Router v4
85	Why you get "Router may have only one child element" warning?
86	How to pass params to history.push method in React Router v4?
87	How to implement default or NotFound page?
88	How to get history on React Router v4?
89	How to perform automatic redirect after login?
	React Internationalization
90	What is React Intl?
91	What are the main features of React Intl?
92	What are the two ways of formatting in React Intl?
93	How to use FormattedMessage as placeholder using React Intl?
94	How to access current locale with React Intl
95	How to format date using React Intl?
	React Testing
96	What is Shallow Renderer in React testing?
97	What is TestRenderer package in React?
98	What is the purpose of ReactTestUtils package?
99	What is Jest?
100	What are the advantages of Jest over Jasmine?
101	Give a simple example of Jest test case
	React Redux
102	What is Flux?
103	What is Redux?
104	What are the core principles of Redux?
105	What are the downsides of Redux compared to Flux?
106	What is the difference between mapStateToProps() and mapDispatchToProps()?
107	Can I dispatch an action in reducer?
108	How to access Redux store outside a component?
109	What are the drawbacks of MVW pattern
110	[Are there any similarities between Redux and