Using custom-generated `roomId` on Colyseus https://discuss.colyseus.io/topic/181/how-to-generate-unique-6-digit-game-code

MyRoomHandler.ts

// npm install nanoid

import * as generateId from "nanoid/generate";

class MyRoomHandler extends Room {
    onInit () {
        // this may introduce colliding `roomId`, use at your own risk
        this.roomId = generateId("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ", 6);
    }
}