content: import React from 'react'
  
  let count = 0
  
  export default class Counter extends React.Component {
    add () {
      count += 1
      this.forceUpdate()
    }
  
    render () {
      return (
        <div>
          <p>Count is: {count}</p>
          <button onClick={() => this.add()}>Add</button>
        </div>
      )
    }
  }
  