JSFiddle - React, Tailwind, and code Playground

HTML

<button id="btn">request gUM</button>

JavaScript

(async () => {



const camera_perm = await navigator.permissions.query( { name: 'camera' } );
camera_perm.onchange = (evt) => {
  const allowed = camera_perm.state === "granted";
  if( allowed ) {
    alert('camera is now allowed');
  }
  else {
    alert('camera is now blocked');
  }
};

btn.onclick = (evt) => {
	navigator.mediaDevices.getUserMedia( { video: true } );
}

})().catch( console.error );