将一个数组扁平化去重排序
var arr = [ [1, 2, 2], [3, 4, 5, 5], [6, 7, 8, 9, [11, 12, [12, 13, [14] ] ] ], 10];
输出[1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
Array.from(new Set(arr.flat(Infinity))).sort((a,b)=>{ return a-b})
new Set(arr.flat(Infinity))//去重扁平化
Array.from将一个类似数组转换为真正的数组
sort是排序
