React: Unable to execute sockets in ComponentDidMount()

JavaScript
#1 
constructor(props) {
    super(props);
    this.state = {
      index: 0,
      timethen: new Date(),
      wordIndex: 0,
      sentenceArray: sentence.split(" "),
      wpm: 0,
      typedWords: "",
    };
    this.socket = io("http://localhost:3000");

    this.handleChange = this.handleChange.bind(this);
    this.createFullSentence = this.createFullSentence.bind(this);
  }
  componentDidMount() {
    var name = prompt("Plese enter your name");
    this.socket.emit("init", name);
  }
  componentDidUpdate() {
    console.log(" I am here ");
    this.socket.emit("update", this.state.wordIndex);
  }

In this the console.log() statement is being executed but the this.socket.emit(“update”,this.stae.wordIndex); statement is not being executed at all!

this is my client side code.

io.on("connection", (socket) => {
    console.log("user connected", socket.id);
    socket.on("init", (name) => {
        socket.broadcast.emit("new-user", name);
        console.log(name);
    });
    socket.on("update", (index) => {
        console.log("You are in index", index);
    });
    socket.on("disconnect", () => {
        console.log(socket.id, "disconnected");
    });
});
#2