js实现快速排序和归并排序

let arr1 = [8,3,9,14,32,2,1,5]
    // 归并排序
    function mergeSort(arr){
      if(arr.length<2)return arr
      let mid = Math.floor(arr.length/2)
      let left = arr.slice(0,mid)
      let right = arr.slice(mid)
      return merge(mergeSort(left),mergeSort(right))
    }
    function merge(left,right){
      let result = []
      while(left.length && right.length){
        if(left[0]<right[0]){
          result.push(left.shift())
        }else{
          result.push(right.shift())
        }
      }
      return result.concat(left,right)
    }

    // 快速排序
    function quickSort(arr){
      if(arr.length<2)return arr
      let mid = Math.floor(arr.length/2)
      let pivot = arr.splice(mid,1)[0]
      let left = [],right = []
      for(let v of arr){
        v<pivot ? left.push(v) : right.push(v)
      }
      return quickSort(left).concat(pivot,quickSort(right))
    }