Detect silence in audio recording

There are similar questions for Java and iOS, but I'm wondering about detecting silence in javascript for audio recordings via getUserMedia(). So given:

navigator.mediaDevices.getUserMedia({ audio: true })
  .then(stream => {
    const mediaRecorder = new MediaRecorder(stream);
    mediaRecorder.start();

    const audioChunks = [];
    mediaRecorder.addEventListener("dataavailable", event => {
      audioChunks.push(event.data);
    });

    mediaRecorder.addEventListener("stop", () => {
      const audioBlob = new Blob(audioChunks);
      const audioUrl = URL.createObjectURL(audioBlob);
      const audio = new Audio(audioUrl);
      audio.play();
    });
  });

I'm wondering if there is anything that can be checked on the Blob, URL, or Audio objects in the stop event for an absence of audio. In the case of a bad microphone or a virtual device selected - anything along those lines. I was previously checking the blob's size, but silent audio still has a filesize. I can do this on the backend via ffmpeg, but hoping there is a way in pure JS to simplify.

from Detect silence in audio recording