Stateful.js

import React, { Component } from 'react';

// Usage:
//
// @Stateful({
//   initialize(props) {
//     return {
//       count: 0
//     };
//   },

//   reducers: {
//     increment(props, state) {
//       return {
//         count: state.count + 1
//       };
//     }
//   }
// })
// class Counter {
//   static propTypes = {
//     count: PropTypes.number.isRequired,
//     increment: PropTypes.func.isRequired
//   };

//   render() {
//     const { count, increment } = this.props;
//     return (
//       <button onClick={increment}>
//         Pressed {count} times.
//       </button>
//     )
//   }
// }

export default function Stateful({ initialize, reducers }) {
  return DecoratedComponent => class StateContainer extends Component {
    constructor(props) {
      super(props);
      this.state = initialize(props);

      this.reducers = {};
      Object.keys(reducers).forEach(key => {
        this.reducers[key] = (...args) => {
          const nextState = reducers[key](this.props, this.state, ...args);
          this.setState(nextState);
        }
      });
    }

    render() {
      return <DecoratedComponent {...this.props}
                                 {...this.state}
                                 {...this.reducers} />;
    }
  }
}