数组flat() 方法

let nestedArray = [1, 2, [3, 4, [5, 6]]];

let flatArray = nestedArray.flat();

console.log(flatArray);

// 输出: [1, 2, 3, 4, [5, 6]]

// 指定深度为 2

let deeplyNestedArray = [1, 2, [3, 4, [5, 6]]];

let deeplyFlatArray = deeplyNestedArray.flat(2);

console.log(deeplyFlatArray);

// 输出: [1, 2, 3, 4, 5, 6]

var arr4 = [1, 2, [3, 4, [5, 6, [7, 8, [9, 10]]]]];

arr4.flat(Infinity);

// [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]