React Higher Order Component with props validation.

HOC.js

import React, { Component, PropTypes } from 'React';

export const Enhance = ComposedComponent => {
  class WrappedComponent extends Component {
    attachFunction() {
      ComposedComponent.attachFunction();
    }
    render() {
      return <ComposedComponent {...this.props} additionalProps={this.state.additionalData} />;
    }
  }
  WrappedComponent.propTypes = {
  };
  return WrappedComponent;
};
export default Enhance;

Cleaned up SBub's implementation for easier copy & paste cuz I just had to. Happy coding!

// Just assume LeftComponent & RightComponent output text in a <p> tag.
const LeftOrRight = (LeftComponent) => {
  const EnhancedComponent = (props) => (
    <Fragment>
      {
        (props.cond === true)
          ? (<LeftComponent {...props}>this component</LeftComponent>)
          : (<RightComponent {...props}>OR this component</RightComponent>)
      }
    </Fragment>
  )

  EnhancedComponent.propTypes = {
    cond: PropTypes.bool,
  }

  EnhancedComponent.defaultProps = {
    cond: true,
  }

  return EnhancedComponent
}

export default LeftOrRight