Commonly used algorithms in js projects

var arr = [1,2,3,4,4,2,2,6,9,1,0];var newArr = [];var onOff = true;for(var i = 0;i<arr.length;i++){
    onOff = true;    for(var j = 0;j<newArr.length;j++){        if(newArr[j]==arr[i]){
            onOff = false;
        }
    }    if(onOff){
        newArr.push(arr[i]);
    }
}console.log(newArr)

function shuffle(arr) {    var i = arr.length, t, j;    while (i) {
        j = Math.floor(Math.random() * i--);
        t = arr[i];
        arr[i] = arr[j];
        arr[j] = t;
    }    console.log(arr)
}var arr = [1, 3, 5, 7, 9]
shuffle(arr)

var str = &#39;abcdefffdddddd&#39;;var obj={};for(var i=0;i<str.length;i++){    var t = str[i];    if(obj[t]){
        obj[t]++;
    }else{
        obj[t] = 1;
    }
}console.log(obj);var max=0,tKey;for(key in obj){    if(obj[key] > max){
        max = obj[key];
        tKey = key;
    }
}console.log(tKey)