Chrome原生应用安装横幅

Question

如果用户已使用以下代码在移动设备中取消或安装了Native App，则本机应用安装横幅无法通知我们。请帮助。

deferredPrompt.userChoice.then(function(choiceResult) {
    console.log('User Choice!'); 
    console.log(choiceResult.outcome);
    choiceElement.textContent = choiceResult.outcome;

    if(choiceResult.outcome == 'dismissed') {
    console.log('Cancelled Install');
    }
    else {
    console.log('User added to homescreen');
    }

    // We no longer need the prompt. Clear it up.
    deferredPrompt = null;
   });