index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<canvas id="sample" width="500" height="2000"></canvas>
<script src="main.js"></script>
</body>
</html>
main.js
const draw = () => {
const xValue = 10;
const yValue = 60;
const xMove = 200;
const textXaxis = 40;
const textYaxis = 20;
const canvas = document.getElementById('sample');
const ctx = canvas.getContext('2d');
const width = canvas.getAttribute('width');
const height = canvas.getAttribute('height');
ctx.clearRect(0, 0, width, height);
ctx.font = "20px arial";
ctx.fillText('Shuffle Alphabet', textXaxis, textYaxis);
const aTozArray = range('A'.charCodeAt(0), 'Z'.charCodeAt(0), 1).map(x => String.fromCharCode(x));
const array = Array.from({length: aTozArray.length}, (v, i) => i);
const randomArray = shuffle(array);
ctx.beginPath();
for (let i = 0; i < aTozArray.length; i++) {
ctx.fillText(aTozArray[i], xValue, yValue * (i + 1));
ctx.fillText(aTozArray[i], xValue + xMove, yValue * (i + 1));
ctx.moveTo(xValue, yValue * (i + 1));
ctx.lineTo(xValue + xMove, yValue * (parseInt(randomArray[i], 10) + 1));
}
ctx.stroke();
}
const shuffle = (array) => {
for(let i = array.length - 1; i > 0; i--){
let r = Math.floor(Math.random() * (i + 1));
let tmp = array[i];
array[i] = array[r];
array[r] = tmp;
}
return array
}
const range = (start, stop, step) => Array.from({ length: (stop - start) / step + 1}, (_, i) => start + (i * step));
draw()
