SOURCE

function selectionSort(arr) {
    var len = arr.length;
    for (var i = 0; i < len; i++) {
        let min = i;
        for (var j = i; j < len; j++) {
            if(arr[min] > arr[j]){
              min = j;
            }
        }
      	let temp = arr[i];   
        arr[i] = arr[min];
        arr[min] = temp;
    }
    return arr;
}
console.log(selectionSort([1,5,3,2,1]))