<!DOCTYPE html>
<html>
<body>
<h1>JavaScript 数组</h1>
<h2>flat() 方法</h2>
<p id="demo"></p>
<script>
const myArr = [1, 2, [3, [4, 5, 6], 7], 8];
const newArr = myArr.flat(2);
document.getElementById("demo").innerHTML = newArr;
</script>
</body>
</html>