Q1: How does React work?
Q2: What is React?
Q3: How would you write an inline style in React?
Q4: What is the use of refs?
Q5: What are props in React?
Q6: What are the advantages of ReactJS?
Q7: What are the major features of ReactJS?
Q8: What is Context API in ReactJS?
Q9: What are React Hooks? Related To: React Hooks
Q10: What are refs used for in React?
Q11: What are the differences between a Class component and Functional component?
Q12: What are the advantages of using React?
Q13: What is the difference between a Presentational component and a Container component?
Q14: What is the difference between state and props?
Q15: What happens when you call setState?
Q16: When rendering a list what is a key and what is it’s purpose?
Q17: What happens during the lifecycle of a React component?
Q18: How is React different from AngularJS (1.x)?
Q19: What does it mean for a component to be mounted in React?
Q20: What’s the difference between a Controlled component and an Uncontrolled one in React?
Q21: What is Reconciliation in ReactJS?
Q22: What is the difference between Component and Container in Redux? Related To: Redux
Q23: What is the difference between Element and Component in ReactJS?
Q24: What is the difference between state and props?
Q25: What are inline conditional expressions in ReactJS?
Q26: What are Controlled components in ReactJS?
Q27: What are Fragments in React?
Q28: What is the purpose of using super constructor with props argument in React?
Q29: What are Stateless components in React?
Q30: What are the limitations of React?
Q31: What is state in React?
Q32: What are two types of components in ReactJS?
Q33: What is the purpose of callback function as an argument of setState?
Q34: How to create refs in React?
Q35: What are portals in React and when do we need them?
Q36: What are Higher-Order Components (HOC) in React?
Q37: What is JSX?
Q38: What are Stateful components in React?
Q39: What are advantages of using React Hooks? Related To: React Hooks
Q40: What is useState() in React? Related To: React Hooks
Q41: How to call loading function with React useEffect only once? Related To: React Hooks
Q42: How to access DOM elements in React? Related To: React Hooks
Q43: How would you prevent a component from rendering in React?
Q44: What is {this.props.children} and when you should use it?
Q45: Name the different lifecycle methods for a class components
Q46: What are Stateless components in React?
Q47: What is the difference between createElement and cloneElement?
Q48: Are you familiar with Flux in the context of React?
Q49: What is the significance of keys in ReactJS?
Q50: What’s the typical pattern for rendering a list of components from an array in React?
Q51: What does shouldComponentUpdate do and why is it important?
Q52: What’s the typical flow of data like in a React + Redux app?
Q53: What’s the difference between an Element and a Component in React?
Q54: What are some limitations of things you shouldn’t do in the component’s render method in React?
Q55: What is the point of shouldComponentUpdate() method?
Q56: What are Pure Components?
Q57: What is the difference between HTML and React event handling?
Q58: How to bind methods or event handlers in JSX callbacks?
Q59: What is Lifting State Up in ReactJS?
Q60: What are the lifecycle methods of ReactJS class components?
Q61: What are the different phases of ReactJS component lifecycle?
Q62: What are Error Boundaries in ReactJS?
Q63: Why we should not update state directly?
Q64: What are forward refs?
Q65: What is children prop?
Q66: What would be the common mistake of function being called every time the component renders?
Q67: What is the difference between ShadowDOM and VirtualDOM?
Q68: What are Uncontrolled components?
Q69: What is Key and benefit of using it in lists?
Q70: Why React uses className over class attribute?
Q71: What is prop drilling and how can you avoid it?
Q72: What’s the difference between useRef and createRef?
Q73: What is StrictMode in React?
Q74: Why do class methods need to be bound to a class instance?
Q75: What do these three dots (…) in React do?
Q76: What’s wrong with using Context in React?
Q77: What is Components Composition in React?
Q78: What does Batching mean in ReactJS? Related To: React Hooks
Q79: What are the advantages of Batching in ReactJS? Related To: React Hooks
Q80: Which lifecycle methods of class component is replaced by useEffect in functional component? Related To: React Hooks
Q81: Compare useState and useReducer implementations Related To: React Hooks
Q82: Do React Hooks cover all use cases for class components? Related To: React Hooks
Q83: How can I make use of Error Boundaries in functional React components? Related To: React Hooks
Q84: When would you use useRef? Related To: React Hooks
Q85: How would you pass data from child to parent component in React?
Q86: What is the purpose of super(props)?
Q87: Explain the Virtual DOM concept in React
Q88: Describe Flux vs MVC? Related To: ASP.NET MVC
Q89: Why doesn’t this.props.children.map work?
Q90: Can you force a React component to rerender without calling setState?
Q91: Describe how events are handled in React
Q92: What’s a Pure Functional Component in React?
Q93: What is the second argument that can optionally be passed to setState and what is its purpose?
Q94: Why would you need to bind event handlers to this?
Q95: Why does React use SyntheticEvents?
Q96: How to apply validation on props in ReactJS?
Q97: How to create Props Proxy for HOC component?
Q98: What is the difference between using constructor vs getInitialState in React?
Q99: When is it important to pass props to super(), and why?
Q100: How to conditionally add attributes to React components?
Q101: When would you use StrictMode component in React?
Q102: How would you go about investigating slow React application rendering?
Q103: Does React re-render all components and sub components every time setState is called?
Q104: What’s the difference between useCallback and useMemo in practice? Related To: React Hooks
Q105: Explain why and when would you use useMemo()? Related To: React Hooks
Q106: When to use useCallback, useMemo and useEffect? Related To: React Hooks
Q107: Can you do Components Inheritance in React?
Q108: What is difference between Incremental DOM and Virtual DOM? Related To: Angular
Q109: When would you use flushSync in ReactJS? Related To: React Hooks
Q110: When shall we use useReducer hook in ReactJS? Related To: React Hooks
Q111: When to use useState vs useReducer? Related To: React Hooks
Q112: How would you store non-state/instance variables in functional React components? Related To: React Hooks
Q113: What is a Pure Function?
Q114: What is React Fiber?
Q115: Explain some difference between Flux and AngularJS (1.x) approach
Q116: How to avoid the need for binding in React?
Q117: What is the key architectural difference between a JavaScript library such as React and a JavaScript framework such as Angular?
Q118: How does React renderer work exactly when we call setState?
Q119: How to use React.memo()?
Q120: Can a custom React hook return JSX? Related To: React Hooks
Q121: What is the order of useInsertionEffect, useEffect and useLayoutEffect hooks at component generation ?
Code Challenges
Q1: Provide an example of any simple Custom React Hook. Why do we need Custom Hooks? Related To: React Hooks
Q2: What is equivalent of the following using React.createElement?
Q3: Given the React code defined above, can you identify two problems?
Q4: What is equivalent of this code using React Hooks? Related To: React Hooks
Q5: What’s wrong with that code?
Q6: If you created a React element like Twitter below, what would the component definition of Twitter look like?
Q7: What is wrong with this code?
Q8: How to mitigate multiple component re-renders when using multiple useState calls? Related To: React Hooks
Q9: How would you optimise this code using one of the React Hooks? Related To: React Hooks
