server.js

const tls = require("tls");
const fs = require("fs");

let server = tls.createServer({
    ca: fs.readFileSync("./ca.crt"),
    cert: fs.readFileSync("./server.crt"),
    key: fs.readFileSync("./server.key"),
    requestCert: true,
    rejectUnauthorized: true
}, (socket) => {
    socket.setEncoding("utf8");
    socket.on("data", (data) => {
        console.log("server.socket.data", data);
        socket.write(data);
    });
    socket.on("end", () => undefined);
    socket.on("error", () => undefined);

    // THIS CRASHES THE SERVER
    console.log(socket.getPeerCertificate());
});
server.listen({ port: 12345 }, () => {
    console.log("listening!")
});