TypeError: Failed to execute 'addTrack' on 'MediaStream': parameter 1 is not of type 'MediaStreamTrack'

Question

I am trying to add and remove an audio track from a stream. The removeTrack function works but the addTrack function throws the error below when it is called

Uncaught TypeError: Failed to execute 'addTrack' on 'MediaStream': parameter 1 is not of type 'MediaStreamTrack'.
    at addAudio (video.jsx:22)
    at HTMLButtonElement.document.querySelector.onclick (video.jsx:32)

Below Is My Code

    componentDidMount = () => {
        var Mstream;
        const video = document.querySelector("video")
        const hasMedia = () => {
            return navigator.getUserMedia = navigator.getUserMedia || navigator.mozGetUserMedia || navigator.webkitGetUserMedia
        }

        const fetchMedia = () => {
            var constraints = { video: true, audio: true }
            navigator.getUserMedia(constraints, (stream) => {
                Mstream = stream
                video.srcObject = stream
            }, (error) => { })
        }

        const addAudio = () => {
            console.log("Adding")
            const audioTracks = Mstream.getAudioTracks()
            Mstream.addTrack(audioTracks[0])
            console.log('Added')
        }

        const removeAudio = () => {
            console.log('removing')
            const audioTracks = Mstream.getAudioTracks()
            Mstream.removeTrack(audioTracks[0])
            console.log('Removed')
        }
        document.querySelector("button#add").onclick = () => addAudio()

        document.querySelector("button#remove").onclick = () => removeAudio()
        hasMedia() && fetchMedia()
    }

EDIT

But it still returns the same error with the addTrack function

        const addAudio = () => {
            console.log("Adding")
            const audioTracks = Mstream.getAudioTracks()
            if(audioTracks.length <= 0){
                Mstream.addTrack(audioTracks[0])
                console.log("Track Added")
            }
            else{
                console.log("Cannot Add Track")
            }

        }

        const removeAudio = () => {
            console.log('removing')
            const audioTracks = Mstream.getAudioTracks()
            if (audioTracks.length > 0) {
                Mstream.removeTrack(audioTracks[0])
            }
            else {
                console.log("Cannot Remove It")
            }
        }

Answer 1

The MediaStream.getAudioTracks() method returns an array of MediaStreamTrack objects. But, it provides no guarantee that there are any elements in the array. audioTracks[0] may be undefined, which would cause this error to occur.