``` try { const l=await navigator.mediaDevices.getUserMedia({audio:!1,video:{facingMode:"user"}}); /* ... */ } catch { this.showError("Could not access webcam. Please check permissions.") } ```

There are alternatives to verify mediaDevices support as https://addpipe.com/getusermedia-examples/

1. `/api/event` endpoint mentioned in the `/stats/script.js` file;

2. There's `/parties/lobby/main/telemetry` in a minified JavaScript chunk asset;

3. There's VitalLens mentioned, and there's an error string in the same asset: "A valid API key or proxy URL is required to use VitalLens. If you signed up recently, please try again in a minute to allow your API key to become active. Otherwise, head to https://www.rouast.com/api to get a free API key."

You see this type of thing in spy movies, but I'm not sure it's that useful in real life. You're basically taking one piece of data a polygraph uses, but without the most important component (skin conductance). Polygraph accuracy isn't that great to begin with. You can profile and manipulate people more effectively based on their reactions and behaviour, and their pulse will be much harder to interpret.