function mergeSort(arr){
if (arr.length===1){
return arr;
}
let len= arr.length;
let middle= Math.floor(len/2);
let left=arr.slice(0,middle);
let right=arr.slice(middle);
return merge(mergeSort(left), mergeSort(right));
}
function merge(left, right){
let leftIndex=0, rightIndex=0;
let resultArr=[];
while(leftIndex<left.length&& rightIndex< right.length){
if(left[leftIndex]<right[rightIndex]){
resultArr.push(left[leftIndex]);
leftIndex++;
}
else{
resultArr.push(right[rightIndex]);
rightIndex++;
}
}
return resultArr.concat(left.slice(leftIndex)).concat(right.slice(rightIndex));
}
console.log(mergeSort([2, 8, 1, 3, 6, 7, 5, 4]));
