counter.js

import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';



class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    }
  }

  incrementCount(){
    debugger
    this.setState({
      count: this.state.count + 1
    });
  }

  decrementCount(){
    this.setState({
      count: this.state.count - 1
    });
  }

  render() {
    return (
      <div className="counter">
        <h1>{this.state.count}</h1>
        <button className="btn" onClick={()=>this.incrementCount()}>Increment</button>
        <button className="btn" onClick={()=>this.decrementCount()}>Decrement</button>
      </div>
    );
  }
}

export default App;