弱引用WeakMap最简单demo

给dom添加额外信息，当dom移除，自动清除

<!DOCTYPE html>
<html lang="en">
  <body>
    <button id="btn">btn</button>
    <script>
      let wm = new WeakMap();
      // console.log('window.btn', window.btn);
      wm.set(window.btn, { aa: 11 });

      setTimeout(() => {
        document.body.removeChild(window.btn);
      }, 2000);

      setInterval(() => {
        console.log(`wm`, wm); //自动清空
      }, 10000);
    </script>
  </body>
</html>
posted @ 2021-12-08 19:08  jerry-mengjie  阅读(36)  评论(0)    收藏  举报