react state in component 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 (
      <div>
        <div>
          {this.state.count}
        </div>
        <button onClick={this.handleIncrement}>Increment by 1</button>
        <button onClick={this.handleDecrement}>Decrement by 1</button>
      </div>
    )
  }
}

Example 2: counter composant react

import React, { useState } from 'react';

function Example() {
  // Déclare une nouvelle variable d'état, que l'on va appeler « count »  const [count, setCount] = useState(0);
  return (
    <div>
      <p>Vous avez cliqué {count} fois</p>
      <button onClick={() => setCount(count + 1)}>
        Cliquez ici
      </button>
    </div>
  );
}

Example 3: set state

setState({ searchTerm: event.target.value })