01_04.数组解构的特殊情况

    <script>
    // 提取下标为5 8 9的值
    // let arr = [1, 2, 1, 1, 2, 3, 4, 5, 6, 7];
    // let [ , , , , , a, , , b, c ] = arr;

    // 提取对象
    // let arr = [ {a:1}, {b:2}, ['哈哈', '嘿嘿'], '你是猪吗' ];
    // let [a, b, c, d] = arr;

    // 数组深层提取
    // let arr = [ {a:1}, {b:2}, ['哈哈', '嘿嘿'], '你是猪吗' ];
    // let [a, b, [, c], d] = arr;

    // 默认值
    let arr = [ 1, 2 ];
    let [a, b = 20, c = 30] = arr; 
    </script>