ConcreteToggle.js

import React, { Component } from 'react';     

class ConcreteToggle extends Component {     
  constructor(props) {     
    super(props);     
    this.state = { isActive: false };     
    this.onToggle = this.onToggle.bind(this);     
  }     

  render() {     
    return (     
      <div>     
        <p onClick={this.onToggle}>title</p>     
        { this.state.isActive && <p>content</p> }     
      </div>     
    );     
  }     

  onToggle() {     
    this.setState({ isActive : !this.state.isActive });     
  }     
}