content: import React from 'react';
  import ReactDOM from 'react-dom';
  import './index.css';
  import caller from './helpers/caller';
  import clocks from './clock/clock'
  "use strict";
  // class Square extends React.Component {
  //     // constructor() {
  //     //     super();
  //     //     this.state = {
  //     //         value: null
  //     //     }
  //     // }
  //     render() {
  //         return (
  //             <button className="square" onClick={() => this.props.onClick()}>
  //                 {this.props.value}
  //             </button>
  //         );
  //     }
  // }
  function Square(props) {
      return (
          <button className="square" onClick={props.onClick}>
              {props.value}
          </button>
      );
  }
  
  class Board extends React.Component {
      constructor() {
          super();
          this.state = {
              squares: Array(9).fill(null),
              xIsNext: true
          }
      }
      componentDidMount() {
          // fetch('sdasda')
      }
      renderSquare(i) {
          return <Square value={this.state.squares[i]} onClick={() => this.handleClick(i)} />;
          }
  
          handleClick(i) {
              const squares = this.state.squares.slice();
              if (calculateWinner(squares) || squares[i]) {
                  return;
              }
              squares[i] = this.state.xIsNext ? 'X' : 'O';
              this.setState({
                  squares: squares,
                  xIsNext: !this.state.xIsNext
              });
          }
  
          render() {
  
              const winner = calculateWinner(this.state.squares);
              let status;
              if (winner) {
                  status = 'Winner: ' + winner;
              } else {
                  status = 'Next player is: ' + (this.state.xIsNext ? 'X' : 'O')
              }
              return (
                  <div>
                      <div className="status">{status}</div>
                      <div className="board-row">
                          {this.renderSquare(0)}
              {this.renderSquare(1)}
              {this.renderSquare(2)}
              </div>
              <div className="board-row">
                  {this.renderSquare(3)}
              {this.renderSquare(4)}
              {this.renderSquare(5)}
              </div>
              <div className="board-row">
                  {this.renderSquare(6)}
              {this.renderSquare(7)}
              {this.renderSquare(8)}
              </div>
          </div>
              );
          }
      }
  
      class Game extends React.Component {
          render() {
          return (
              <div className="game">
                  <div className="game-board">
                      <Board />
                  </div>
                  <div className="game-info">
                      <div>{/* status */}</div>
                      <ol>{/* TODO */}</ol>
                  </div>
              </div>
              );
      }
  }
  
  function calculateWinner(squares) {
      const lines = [
          [0, 1, 2],
          [3, 4, 5],
          [6, 7, 8],
          [0, 3, 6],
          [1, 4, 7],
          [2, 5, 8],
          [0, 4, 8],
          [2, 4, 6]
      ];
      for (let i = 0; i < lines.length; i++) {
          const [a, b, c] = lines[i];
          if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) {
              return squares[a];
          }
      }
      return null;
  }
  // ========================================
  function tick() {
      const el = (<div>
          <h1>Hello, world!</h1>
          <h2>It is {new Date().toLocaleTimeString()}.</h2>
      </div>);
      ReactDOM.render(
          el,
          document.getElementById('root')
      );
  };
  
  // ReactDOM.render(
  //     el,
  //     document.getElementById('root')
  // );
  
  setInterval(tick, 1000);
  