state in classes react code example

Example 1: set state

class App extends React.Component {

state = { count: 0 }

handleIncrement = () => {
  this.setState({ count: this.state.count + 1 })
}

handleDecrement = () => {
  this.setState({ count: this.state.count - 1 })
}
  render() {
    return (
      

        

          {this.state.count}
        
        Increment by 1
        Decrement by 1
      
    )
  }
}

Example 2: how to write statefull class in react

import React, {Component} from 'react'

class Pigeons extends Component {
  constructor() {
    super()
    this.state = {
      pigeons: []
    }
  }
  render() {
    return (
      

        
Look at all the pigeons spotted today!
        

          {this.state.pigeons.map(pigeonURL => {
            return 

          })}
        
      
    )
  }
}