#1. Use Functional Components

Functional components are the preferred way of writing React components. They are more concise and easier to read than class components. Here's an example:

function MyComponent(props) {
  return <div>{props.text}</div>;
}

#2. Destructure Props

Destructuring props at the component's parameter level makes your code cleaner and more readable.

function MyComponent({ text }) {
  return <div>{text}</div>;
}

#3. State Management with Hooks

Use React Hooks like useState and useEffect for state management and side effects. Hooks make your code more concise and easier to reason about.

import React, { useState, useEffect } from 'react';

function MyComponent() {
  const [count, setCount] = useState(0);

  useEffect(() => {
    document.title = `Count: ${count}`;
  }, [count]);

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

#4. Separate Concerns with Components

Follow the Single Responsibility Principle. Divide your application into smaller, reusable components that focus on one specific task.

#5. Use Prop Types or TypeScript

Use Prop Types or TypeScript to define the expected data types for your component's props. This helps catch errors early and documents the component's interface.

import PropTypes from 'prop-types';

function MyComponent(props) {
  // ...
}

MyComponent.propTypes = {
  text: PropTypes.string.isRequired,
};

#6. Avoid Conditional Rendering in JSX

Instead of complex ternary operators in JSX, conditionally render components based on variables or state outside the return statement.

function MyComponent({ isLoading, data }) {
  if (isLoading) {
    return <LoadingSpinner />;
  }

  return <DataComponent data={data} />;
}

#7. Use CSS Modules or Styled Components

To maintain clean and modular styles, use CSS Modules or styled-components to encapsulate component-specific styles.

#8. Avoid Inline Styles

Avoid using inline styles in your JSX, as they can make your code harder to maintain. Instead, use CSS or a styling solution like styled-components.

#9. Optimize Renders with PureComponent or React.memo

For performance optimization, use PureComponent for class components and React.memo for functional components to prevent unnecessary re-renders.

import React, { PureComponent } from 'react';

class MyComponent extends PureComponent {
  // ...
}

#10. Keep an Eye on the Component Hierarchy

Be mindful of your component hierarchy. Deeply nested components can make the code harder to understand. Consider using context or a state management library to avoid excessive prop drilling.

In conclusion, following these best practices will help you maintain clean, readable, and maintainable React.js code. Clean code not only makes your development process smoother but also ensures your application is more robust and easier to collaborate on with other developers. Happy coding!