What are React Mixins?

⚠️ DEPRECATED: Mixins are considered legacy and should not be used in modern React applications.

_Mixins_ were a way to share common functionality between components using React.createClass(). However, they caused several problems:

• Implicit dependencies
• Name clashes
• Snowballing complexity

One of the most commonly used mixins was PureRenderMixin:

    const PureRenderMixin = require("react-addons-pure-render-mixin");

    const Button = React.createClass({
      mixins: [PureRenderMixin],
      // ...
    });
    

Modern Alternatives:

• React.memo() for functional components (replaces PureRenderMixin)
• Custom Hooks for sharing stateful logic
• Higher-Order Components (HOCs) for cross-cutting concerns
• Render Props pattern

    // Modern equivalent using React.memo
    const Button = React.memo(({ onClick, label }) => (
      <button onClick={onClick}>{label}</button>
    ));