var arr = [1,2,3]
var newArr = []
upData (arr, index) {
if (this.arr.length > 1 && index !== 0) {
newArr = swapItems(arr, index, index - 1)
}
}
downData (arr, index) {
if (this.arr.length > 1 && index !== (this.arr.length - 1)) {
newArr = swapItems(this.arr, index, index + 1)
}
}
