How come a MediaStream object is {} JSON?

Question

I have a MediaStream object that points to a live stream. It is stored in a variable called vs. This is my console:

> vs
< MediaStream {id: "MEDIASTREAMID", active: true, ...}

> JSON.stringify({Livestream:vs})
< "{"Livestream":{}}"

How come a MediaStream object is {} in JSON?

Edit:

Here is an example:

var canvas = document.querySelector("canvas");
var context = canvas.getContext("2d");
const video = document.querySelector('#myVidPlayer');
var w, h;
canvas.style.display = "none";
function snapshot(){
    context.fillRect(0, 0, w, h);
    context.drawImage(video, 0, 0, w, h);
    canvas.style.display = "block";
}
var vs;
window.navigator.mediaDevices.getUserMedia({ video: true, audio: true })
    .then(function(stream){
        video.srcObject = stream;
        vs=stream;
        console.log(JSON.stringify({Livestream:stream}));
        video.onloadedmetadata = (e) => {
            video.play();
            w = video.videoWidth;
            h = video.videoHeight
            canvas.width = w;
            canvas.height = h;
        };
    }).catch(function(e){
        alert('You have to enable the microphone and the camera');
    });

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8"/>
        <title>Livestream</title>
    </head>
    <body style="margin:0">
        <video id="myVidPlayer" style="width:100%;height:100%" muted autoplay></video>
        <button onclick="snapshot()" >Snapshot</button>
        <div class="mycanvas">
            <h2>Captured snapshot</h2>
            <p>Right click and save the image</p>
            <canvas></canvas>
        </div>
    </body>
</html>

`MediaStream` is an object. What did you expect to be instead? — evolutionxbox, Feb 24 '21 at 20:06
@evolutionxbox: But it isn't an empty object. I expected it to be with it's `id`, `active`, `onaddtrack` and other things. — Lakshya Raj, Feb 24 '21 at 20:07
May you update the question so we can see a runnable [mcve]? — evolutionxbox, Feb 24 '21 at 20:07
There's not enough posted here to determine what is going on. — Pointy, Feb 24 '21 at 20:07
If I run the code posted I get `"{\"Livestream\":{\"id\":\"MEDIASTREAMID\",\"active\":true}}"` — evolutionxbox, Feb 24 '21 at 20:09
Thanks for adding the runnable example. I don't see a `JSON.stringify` call in there though? — evolutionxbox, Feb 24 '21 at 20:10
@ everyone: Thanks for marking this as duplicate. I'll use the other question to answer my own. — Lakshya Raj, Feb 24 '21 at 20:16
@LakshyaRaj does the duplicate answer your question? I found that `JSON.stringify(new MediaStream()) // "{}"` — evolutionxbox, Feb 24 '21 at 20:18
@evolutionxbox: Well, not exactly, but I'll try to store something else in `localStorage` that would be equivalent to a MediaStream, for example an array of its properties that I need to rebuild it. — Lakshya Raj, Feb 24 '21 at 20:19

How come a MediaStream object is {} JSON?

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