Language: TypeScript
Label: vulnerable
CWE: CWE-79 \u2014 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Code:
    function sendPrivateMessage() {
        let pMsg = checkMsg(msgerPrivateMsgInput.value.trim());
        if (!pMsg) {
            msgerPrivateMsgInput.value = '';
            isChatPasteTxt = false;
            return;
        }
        let toPeerName = msgerPrivateBtn.value;
        emitMsg(myPeerName, toPeerName, pMsg, true, peerId);
        appendMessage(myPeerName, rightChatAvatar, 'right', pMsg + '<hr>Private message to ' + toPeerName, true);
        msgerPrivateMsgInput.value = '';
        msgerCP.style.display = 'none';
    }