const array = [1, 2, 3, 4, 5, 6, 7, 8, 9];

const arraylength = array.length;

//フィッシャーイェーツのアルゴリズム
for (let i = arraylength - 1; i >= 0; i--) {
const randomIndex = Math.floor(Math.random() * (i + 1));
[array[i], array[randomIndex]] = [array[randomIndex], array[i]];
}