Difference between mixins and higher-order components (as ES7 decorators).

component-with-decorator.js

import React from 'react';

function animateIn(Component){
  return class DecoratedComponent extends React.Component {
    componentWillEnter(){
      // Do some swanky animation
    }
    
    render(){
      // Inherit all props
      return <Component {...this.props} />;
    }
  }
}

@animateIn
class MyComponent extends React.Component {
  render(){
    return <h1>Hello world!</h1>;
  }
}

createclass.js

var React = require('react');
var AnimateIn = require('../mixins/AnimateIn');

var MyComponent = React.createClass({
  mixins: [AnimateIn],
  render: function(){
    <h1>Hello world!</h1>
  }
});

module.exports = MyComponent;