For any website on the internet (not specific to perchance):

• If you’re not using a VPN, then your IP is visible to any webpage you visit. From your IP, the author of the page can guess at your country/state/region (definitely not street address or anything close to that, to be clear).
• If you are using a reputable VPN, and you’ve got their browser extension installed, then it shouldn’t be possible for anyone to see your IP, regardless of whether WebRTC is being used on the page (via peerjs or any other multiplayer/peer-to-peer type frameworks). For example, I know that the NordVPN browser extension enables WebRTC leak protection by default.
• A side note just to clarify: peerjs is not a malicious script - it’s used all over the internet for multiplayer games, video conferencing, and that type of thing.

TL;DR: If you want to hide your IP, you need to use a reputable VPN like NordVPN, and make sure you’ve got their browser extension installed. This applies to any website on the internet, not just perchance, to be clear.