1 2 3 4 5 6 7 8 9 10 11 12 13 14 15const io = require("socket.io-client"); const socket = io("http://localhost:3000"); const group = process.env.GROUP || "B"; socket.on("connect", () => { console.log("connected"); socket.emit("join-group", group, () => { console.log(`group ${group} joined`); }); }); socket.on("only-group-A", () => { console.log("should not happen"); });