数组扁平化处理

// 数组扁平化排序处理
var arr = [[1, 2, 2], [3, 4, 5, 5], [6, 7, 8, 9, [11, 12, [12, 13, [14]]]], 10];
//1
Array.prototype.flat = function () {
 return [].concat(...this.map(item => (Array.isArray(item) ? item.flat() : item)));
}

Array.prototype.unique = function () {
 return [...new Set(this)]
}

const sort = (a, b) => a - b;

console.log(arr.flat().unique().sort(sort));
//2
console.log([...new Set(String(arr).split(','))].map(Number).sort((a,b)=>a-b))
//3
console.log([...new Set(arr.join(',').split(','))].map(Number).sort((a, b) => a - b))