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Pramod K 💻
Pramod K 💻

Posted on • Updated on

Performance optimization techniques that can be applied to React applications to improve their performance

React is one of the most popular frontend frameworks used for developing user interfaces. Performance optimization is essential for building a successful React application. If performance issues are not addressed, it can lead to poor user experience, slow loading times, and ultimately, a failed application. Here are 10 performance optimization techniques that can be applied to React applications to improve their performance.

Memo

Use React.memo: React.memo is a higher order component that memoizes a functional component and skips re-rendering if its props remain the same. This is a great way to improve performance when a component is not changing its props.

const MyComponent = ({ user }) => {
  return <div>{user.name}</div>;
};

export default React.memo(MyComponent);

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Use the useMemo Hook: useMemo is a hook that memoizes a value so it is not recalculated every render. This can be useful for optimizing expensive calculations that are used in components.

const MyComponent = ({ user }) => {
  const name = useMemo(() => {
    // Do an expensive calculation
    return user.name;
  }, [user]);

  return <div>{name}</div>;
};
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Use React.PureComponent: PureComponent is similar to React.memo in that it skips re-rendering if its props remain the same. However, it works for class components, which can be more performant than functional components.

class MyComponent extends React.PureComponent {
  render() {
    const { user } = this.props;
    return <div>{user.name}</div>;
  }
}
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Lazy loading

Use React.lazy and Suspense: React.lazy allows you to dynamically import components, which is a great way to improve performance by splitting up your code into smaller chunks. This can be combined with the Suspense component to show a fallback UI while the code is being imported.

const MyComponent = React.lazy(() => import('./MyComponent'));

const App = () => (
  <Suspense fallback={<div>Loading...</div>}>
    <MyComponent />
  </Suspense>
);
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shouldComponentUpdate / useEffect

Use shouldComponentUpdate: shouldComponentUpdate() is a lifecycle method that allows you to determine if a component should re-render or not. This can be useful for optimizing components that render expensive operations.

class MyComponent extends React.Component {
  shouldComponentUpdate(nextProps, nextState) {
    const { user } = this.props;
    return user.name !== nextProps.user.name;
  }
  render() {
    const { user } = this.props;
    return <div>{user.name}</div>;
  }
}
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Use the useEffect Hook: useEffect is a hook that allows you to determine if a component should re-render or not. This can be useful for optimizing components that render expensive operations.

const MyComponent = ({ user }) => {
  const [name, setName] = useState(user.name);
  const shouldUpdate = useRef(true);

  useEffect(() => {
    if (user.name !== name) {
      shouldUpdate.current = true;
      setName(user.name);
    } else {
      shouldUpdate.current = false;
    }
  }, [user.name]);

  useEffect(() => {
    if (shouldUpdate.current) {
      // Do something expensive
    }
  }, [name]);

  return <div>{name}</div>;
};
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React Fragment

Use the React.Fragment Component: Fragments can be used to wrap multiple elements without adding extra nodes to the DOM. This can be useful for optimizing components with many elements.

const MyComponent = () => (
  <React.Fragment>
    <div>Element 1</div>
    <div>Element 2</div>
    <div>Element 3</div>
  </React.Fragment>
);
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callback hook

Use the useCallback Hook: useCallback is a hook that memoizes a function so it is not recreated every render. This can be useful for optimizing functions that are passed as props to child components.

const MyComponent = ({ user }) => {
  const handleClick = useCallback(() => {
    // Do something
  }, [user]);

  return <button onClick={handleClick}>Click me</button>;
};
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Ref

Use the useRef Hook: useRef is a hook that allows you to create a mutable object that will persist between renders. This can be useful for optimizing components that need to store state that does not trigger a re-render.

const MyComponent = () => {
  const ref = useRef({ counter: 0 });

  ref.current.counter += 1;

  return <div>Counter: {ref.current.counter}</div>;
};
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Context

Use the useContext Hook: useContext is a hook that allows you to access context from a component. This can be useful for optimizing components that need to access the same data from multiple components.

const MyContext = React.createContext();

const MyComponent = () => {
  const value = useContext(MyContext);

  return <div>{value}</div>;
};
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