SOURCE

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


function shuffle(arr){
    let m = arr.length;

    while(m>1){
        let index = ~~(Math.random()*m--);
        [arr[index], arr[m]] = [arr[m], arr[index]]
    }

    return arr;
}

console.log(shuffle(arr))