import React, { Component } from 'react'; const withDevTools = // process.env.NODE_ENV === 'development' && typeof window !== 'undefined' && window.__REDUX_DEVTOOLS_EXTENSION__; class Counter extends Component { constructor() { super(); this.state = { counter: 0 }; this.increment = this.increment.bind(this); this.decrement = this.decrement.bind(this); } componentWillMount() { if (withDevTools) { this.devTools = window.__REDUX_DEVTOOLS_EXTENSION__.connect(); this.unsubscribe = this.devTools.subscribe((message) => { // Implement monitors actions. // For example time traveling: if ( message.type === 'DISPATCH' && message.payload.type === 'JUMP_TO_STATE' ) { this.setState(message.state); } }); } } componentWillUnmount() { if (withDevTools) { this.unsubscribe(); // Use if you have other subscribers from other components. window.__REDUX_DEVTOOLS_EXTENSION__.disconnect(); // If there aren't other subscribers. } } increment() { const state = { counter: this.state.counter + 1 }; if (withDevTools) this.devTools.send('increment', state); this.setState(state); } decrement() { const state = { counter: this.state.counter - 1 }; if (withDevTools) this.devTools.send('decrement', state); this.setState(state); } render() { const { counter } = this.state; return (

Clicked: {counter} times {' '}

); } } export default Counter;