Question

QUESTION: This is a tic-tac-toe game in react.js. Covert the following class-based components in React.js to Functional Based component in React.

//CODE
import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
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 Square(props) {
return (

{props.value}

);
}

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

render() {
return (

{this.renderSquare(0)}
{this.renderSquare(1)}
{this.renderSquare(2)}

{this.renderSquare(3)}
{this.renderSquare(4)}
{this.renderSquare(5)}

{this.renderSquare(6)}
{this.renderSquare(7)}
{this.renderSquare(8)}

);
}
}

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

handleClick(i) {
let 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";
const stepNumber = history.length;
history = history.concat([{squares}]);
const xIsNext = !this.state.xIsNext;
this.setState({
history, stepNumber, 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>
);
}

}

// ========================================

ReactDOM.render(, document.getElementById("root"))

Answer 1

import React { useState } from 'react';
import ReactDOM from 'react-dom';
import './index.css';
const 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;
}

const function Square(props) {
return (

{props.value}

);
}

const function Board(props) {
renderSquare(i) {
return (
value={props.squares[i]}
onClick={() => props.onClick(i)}
/>
);
}

return (

{renderSquare(0)}
{renderSquare(1)}
{renderSquare(2)}

{renderSquare(3)}
{renderSquare(4)}
{renderSquare(5)}

{renderSquare(6)}
{renderSquare(7)}
{renderSquare(8)}

);

}

const function Game(props) {

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

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

const current = history[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={() => jumpTo(move)}>{desc}</button>
</li>
);
});

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

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

}

// ========================================

ReactDOM.render(, document.getElementById("root"))