浅克隆一个Map

<script>
  // 集合set 和映射map构造的时候，都用new Set 和new Map来
  // 构造一个map
  const xiaoming = new Map([
    ["username", "xiaoming"],
    ["age", 19],
    ["sex", "male"],
    ["height", 188],
  ]);
  const xiaohong = new Map(xiaoming);
  console.log(xiaohong);
</script>