使用es6使數組的第一項和最后一項就行調換

let arr = [1, 2, 3,4];
let a = arr.filter((item, index) => {
  return index > 0 && index < (arr.length - 1)
});
let arr2 = [arr[arr.length-1],...a,arr[0]];
console.log(arr2)