PWA添加到主屏幕弹出按钮不起作用

Question

我正在尝试添加弹出按钮以下载渐进式Web应用程序（PWA）并添加到主屏幕。老实说，我不知道我在哪里弄错了。

let deferredPrompt;
const addBtn = document.querySelector('#add');
addBtn.style.display = 'none';

window.addEventListener('beforeinstallprompt', (e) => {
  e.preventDefault();
  deferredPrompt = e;
  addBtn.style.display = 'block';

  addBtn.addEventListener('click', (e) => {
    addBtn.style.display = 'block';
    deferredPrompt.prompt();

    deferredPrompt.userChoice.then((choiceResult) => {
      if (choiceResult.outcome === 'accepted') {
        console.log('User accepted the A2HS prompt');
      } else {
        console.log('User dismissed the A2HS prompt');
      }
      deferredPrompt = null;
    });
  });
});

.add-button {
  position: absolute;
  top: 1px;
  left: 1px;
}

<button id="add">Add to home</button>