zadanie01.jsx

import React from 'react';
import ReactDOM from 'react-dom';

document.addEventListener('DOMContentLoaded', function(){
    class Buttons extends React.Component {
        constructor(props){
            super(props);

            let generatedTexts = [];

            for( let i = 0; i < 15; i++ ) {
                generatedTexts.push( 'Klik!' );
            }

            this.state = {
                texts : generatedTexts
            };
        }
        handleButtonClick = (e, index) => {
            const textsCopy = this.state.texts.slice();
            textsCopy[index] = 'Kliknięty.';

            this.setState({
                texts : textsCopy,
            });
        };
        render(){
            let buttons = [];

            for( let i = 0; i < 15; i++ ){
                const newButton = <button
                    onClick={e => this.handleButtonClick(e, i)}
                >
                    { this.state.texts[i] }
                </button>;

                buttons.push( newButton );
            }

            return <div>
                { buttons }
            </div>;
        }
    }

    class App extends React.Component {
        render(){
            return <Buttons />;
        }
    }

    ReactDOM.render(
        <App />,
        document.getElementById('app')
    );
});