ai/audio-recorder-polyfill

navigator.mediaDevices.getUserMedia({ audio: true }).then(stream => {
  recorder = new MediaRecorder(stream)
  recorder.addEventListener('dataavailable', e => {
    audio.src = URL.createObjectURL(e.data)
  })
  recorder.start()
})

npm install --save audio-recorder-polyfill

  entry: {
    app: './src/app.js',
+   polyfill: './src/polyfill.js'
  }

import AudioRecorder from 'audio-recorder-polyfill'
window.MediaRecorder = AudioRecorder

+   <script>
+     if (!window.MediaRecorder) {
+       document.write(
+         decodeURI('%3Cscript defer src="/polyfill.js">%3C/script>')
+       )
+     }
+   </script>
    <script src="/app.js" defer></script>

import AudioRecorder from 'https://cdn.jsdelivr.net/npm/audio-recorder-polyfill/index.js'
window.MediaRecorder = AudioRecorder

if (MediaRecorder.notSupported) {
  noSupport.style.display = 'block'
  dictaphone.style.display = 'none'
}

let recorder

recordButton.addEventListener('click', () => {
  // Request permissions to record audio
  navigator.mediaDevices.getUserMedia({ audio: true }).then(stream => {
    recorder = new MediaRecorder(stream)

    // Set record to <audio> when recording will be finished
    recorder.addEventListener('dataavailable', e => {
      audio.src = URL.createObjectURL(e.data)
    })

    // Start recording
    recorder.start()
  })
})

stopButton.addEventListener('click', () => {
  // Stop recording
  recorder.stop()
  // Remove “recording” icon from browser tab
  recorder.stream.getTracks().forEach(i => i.stop())
})

// Will be executed every second with next part of audio file
recorder.addEventListener('dataavailable', e => {
  sendNextPiece(e.data)
})
// Dump audio data every second
recorder.start(1000)

recorder.addEventListener('dataavailable', e => {
  e.data.type //=> 'audio/wav' with polyfill
              //   'audio/webm' in Chrome
              //   'audio/ogg' in Firefox
})

import AudioRecorder from 'audio-recorder-polyfill'
import mpegEncoder from 'audio-recorder-polyfill/mpeg-encoder'

AudioRecorder.encoder = mpegEncoder
AudioRecorder.prototype.mimeType = 'audio/mpeg'
window.MediaRecorder = AudioRecorder

  import AudioRecorder from 'audio-recorder-polyfill'
+ import customEncoder from './ogg-opus-encoder'
+
+ AudioRecorder.encoder = customEncoder
+ AudioRecorder.prototype.mimeType = 'audio/ogg'
  window.MediaRecorder = AudioRecorder

module.exports = () => {
  function init (sampleRate) {
    …
  }

  function encode (input) {
    …
  }

  function dump (sampleRate) {
    …
    postMessage(output)
  }

  onmessage = e => {
    if (e.data[0] === 'init') {
      init(e.data[1])
    } else if (e.data[0] === 'encode') {
      encode(e.data[1])
    } else if (e.data[0] === 'dump') {
      dump(e.data[1])
    }
  }
}