1 if (!Array.prototype.flat) {
2 Array.prototype.flat = function (num = 1) {
3 if (!Number(num) || Number(num) < 0) {
4 return this;
5 }
6 var arr = []
7 this.forEach((item) => {
8 if (Array.isArray(item)) {
9 arr = arr.concat(item.flat(--num))
10 } else {
11 arr.push(item)
12 }
13 })
14 return arr
15 }
16 }
测试用例
1 const arr = [1, [2, [3, 'a', [4]]]]
2
3 console.log(arr.flat('dsdsadf')); // [1, [2, [3, 'a', [4]]]]
4 console.log(arr.flat(-32)); // [1, [2, [3, 'a', [4]]]]
5 console.log(arr.flat(0)); // [1, [2, [3, 'a', [4]]]]
6 console.log(arr.flat('1')); // [1, 2, [3, 'a', [4]]]
7 console.log(arr.flat('2')); // [1, 2, 3, 'a', [4]]
8 console.log(arr.flat(3)); // [1, 2, 3, 'a', 4]
9 console.log(arr.flat(Infinity)); // [1, 2, 3, 'a', 4]
10 console.log(arr.flat('Infinity')); // [1, 2, 3, 'a', 4]
