Fisher-Yates-In-Place-Shuffle.js

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

function getRandomInt(max) {
  return Math.floor(Math.random() * Math.floor(max));
}

console.log("Initial Array", arr);

for(let i = (arr.length - 1); i > 0; i--){
  const randI = getRandomInt(i);
  [arr[randI], arr[i]] = [arr[i], arr[randI]]; 
}

console.log("Final Array", arr);