How to Build a Game with React Js?

Introduction

Building a small game with React.js can be a fun and educational project. Here's a step-by-step guide to creating a simple "Tic-Tac-Toe" game with React.

Step 1. Set Up the Project

Install Node.js: Ensure you have Node.js installed on your machine.
Create a React App: Use Create React App to set up a new project.

npx create-react-app tic-tac-toe
cd tic-tac-toe
npm start

Step 2. Create the Game Board

Define Components

Square: A functional component for each square.
Board: A class component that manages the state of the squares.
Game: A class component that manages the overall game state.

Component Structure

Square: Renders a button.
Board: Renders 9 Square components.
Game: Manages the game's state and contains the Board component.

Step 3. Build the Components

Square Component

// src/components/Square.js
import React from 'react';

const Square = ({ value, onClick }) => (
  <button className="square" onClick={onClick}>
    {value}
  </button>
);

export default Square;

Square Component

// src/components/Board.js
import React from 'react';
import Square from './Square';

class Board extends React.Component {
  renderSquare(i) {
    return (
      <Square 
        value={this.props.squares[i]} 
        onClick={() => this.props.onClick(i)} 
      />
    );
  }

  render() {
    return (
      <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>
    );
  }
}

export default Board;

Game Component

// src/components/Game.js
import React from 'react';
import Board from './Board';

class Game extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      history: [{
        squares: Array(9).fill(null),
      }],
      stepNumber: 0,
      xIsNext: true,
    };
  }

  handleClick(i) {
    const history = this.state.history.slice(0, this.state.stepNumber + 1);
    const current = history[history.length - 1];
    const squares = current.squares.slice();
    if (calculateWinner(squares) || squares[i]) {
      return;
    }
    squares[i] = this.state.xIsNext ? 'X' : 'O';
    this.setState({
      history: history.concat([{
        squares: squares,
      }]),
      stepNumber: history.length,
      xIsNext: !this.state.xIsNext,
    });
  }

  jumpTo(step) {
    this.setState({
      stepNumber: step,
      xIsNext: (step % 2) === 0,
    });
  }

  render() {
    const history = this.state.history;
    const current = history[this.state.stepNumber];
    const winner = calculateWinner(current.squares);

    const moves = history.map((step, move) => {
      const desc = move ?
        'Go to move #' + move :
        'Go to game start';
      return (
        <li key={move}>
          <button onClick={() => this.jumpTo(move)}>{desc}</button>
        </li>
      );
    });

    let status;
    if (winner) {
      status = 'Winner: ' + winner;
    } else {
      status = 'Next player: ' + (this.state.xIsNext ? 'X' : 'O');
    }

    return (
      <div className="game">
        <div className="game-board">
          <Board
            squares={current.squares}
            onClick={(i) => this.handleClick(i)}
          />
        </div>
        <div className="game-info">
          <div>{status}</div>
          <ol>{moves}</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;
}

export default Game;

Step 4. Style the Game

CSS Styling

/* src/index.css */
.square {
  background: #fff;
  border: 1px solid #999;
  float: left;
  font-size: 24px;
  font-weight: bold;
  line-height: 34px;
  height: 34px;
  margin-right: -1px;
  margin-top: -1px;
  padding: 0;
  text-align: center;
  width: 34px;
}

.board-row:after {
  clear: both;
  content: "";
  display: table;
}

.game {
  display: flex;
  flex-direction: row;
}

.game-info {
  margin-left: 20px;
}

Step 5. Assemble and Run the Game

Update App.js

// src/App.js
import React from 'react';
import Game from './components/Game';
import './App.css';

function App() {
  return (
    <div className="App">
      <Game />
    </div>
  );
}

export default App;

Run the App

npm start

React App

Conclusion

You've now built a simple Tic-Tac-Toe game with React! This project covers essential React concepts such as components, state management, event handling, and conditional rendering. You can further enhance the game by adding features like a scoreboard, reset functionality, and enhanced styling.