Mastering the ReactJS Interview: Top 12 Questions

1. Explain React Router and its use in a single page application (SPA)

Answer: React Router is a standard library for navigation in React applications. It enables the development of SPAs by allowing the creation of routes that map to different components.

import { BrowserRouter as Router, Route, Link } from 'react-router-dom';

const App = () => (
  <Router>
    <div>
      <nav>
        <ul>
          <li>
            <Link to="/">Home</Link>
          </li>
          <li>
            <Link to="/about">About</Link>
          </li>
        </ul>
      </nav>

      <Route path="/" exact component={Home} />
      <Route path="/about" component={About} />
    </div>
  </Router>
);

2. What is Redux and how does it work with React?

Answer: Redux is a state management library that helps manage the state of a React Application. It mantains a single source of truth (the store) and uses actions and reducers to update the state.

// Action
const increment = () => ({
  type: 'INCREMENT',
});

// Reducer
const counterReducer = (state = 0, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return state + 1;
    default:
      return state;
  }
};

// Store
const store = createStore(counterReducer);

// React Component
const CounterComponent = () => {
  const count = useSelector((state) => state);
  const dispatch = useDispatch();

  return (…