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What is the Purpose of displayName Class Property in ReactJS?

The displayName property in React is used primarily for debugging purposes. It helps in identifying components in debugging tools like React DevTools and in error messages. By setting the displayName property, you can give a meaningful name to a component, which is especially useful for components created using higher-order components (HOCs) or those without a clear name in the code.

Using displayName in Functional Components

For functional components, you can set the displayName property directly on the function or the component after its definition.

Example

import React from 'react';

const MyComponent = () => {
  return <div>Hello, World!</div>;
};

MyComponent.displayName = 'CustomMyComponent';

export default MyComponent;

In this example, MyComponent will appear as CustomMyComponent in debugging tools.

Using displayName in Class Components

For class components, you can set the displayName property on the class itself.

Example

import React, { Component } from 'react';

class MyComponent extends Component {
  render() {
    return <div>Hello, World!</div>;
  }
}

MyComponent.displayName = 'CustomMyComponent';

export default MyComponent;

Here, MyComponent will appear as CustomMyComponent in debugging tools.

Using displayName with Higher-Order Components (HOCs)

Higher-order components often wrap other components, which can make the component tree in debugging tools less clear. Setting the displayName helps clarify which components are being wrapped.

Example

import React from 'react';

const withExtraInfo = (WrappedComponent) => {
  const HOC = (props) => {
    return <WrappedComponent {...props} />;
  };

  HOC.displayName = `withExtraInfo(${WrappedComponent.displayName || WrappedComponent.name || 'Component'})`;

  return HOC;
};

const MyComponent = () => {
  return <div>Hello, World!</div>;
};

const EnhancedComponent = withExtraInfo(MyComponent);

export default EnhancedComponent;

In this example, EnhancedComponent will appear as withExtraInfo(MyComponent) in debugging tools, making it clear that MyComponent is wrapped by the withExtraInfo HOC.

Benefits of displayName

  1. Improved Debugging: It makes it easier to identify components in tools like React DevTools.
  2. Clearer Error Messages: Errors and warnings will include the custom display name, making it easier to locate the source of the issue.
  3. Better Readability: When working with HOCs or dynamically created components, setting a displayName provides a clearer picture of the component structure.

Conclusion

The displayName property in React is a valuable tool for improving the development and debugging experience. By explicitly setting meaningful names for your components, especially those created with HOCs or other dynamic patterns, you can make your codebase more maintainable and easier to work with.


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