方法一：

function slasher(arr, howMany) {
// it doesn't always pay to be first
arr=arr.slice(howMany);
 return arr;
}
slasher([1, 2, 3], 2);

方法二：

function slasher(arr, howMany) {
  // it doesn't always pay to be first
  if(howMany === 0){
    return arr;
  }
  if(arr.length <= howMany){
    return [];
  }else{
    arr.splice(0,howMany);
    return arr;
  }
}


slasher([1, 2, 3], 2);