When app.js
receives data sent from the server (displayed in the console), setState
does not refresh the web page with the new data. In the line console.log("Received data queue:", data.queue)
, it also returns undefined
. I expected it to be a specific value because in the line console.log(data)
it has the value stored under the "queue" key.
This is my code:
import React, { Component } from "react"; import { TransitionGroup, CSSTransition } from "react-transition-group"; import "./chat.css"; import "./styles.css"; import "./queue.css"; import Chat from "./chat"; import io from "socket.io-client"; class App extends Component { constructor(props) { super(props); this.state = { queue: [], instruction: "", user: "", hal: "", status: "waiting" }; } componentDidMount() { const socket = io("http://localhost:5000"); socket.on("connect", () => { console.log("Connected to the socket server"); }); socket.on("queueData", (data) => { console.log("Received data:", data); console.log("Received data queue:", data.queue); this.setState({ queue: data.queue }, () => { console.log(this.state.queue); }); this.setState({ instruction: data.instruction }, () => { console.log(this.state.instruction); }); // other attributes, user, hal, status ignored here for simplicity }); this.socket = socket; } componentWillUnmount() { this.socket.disconnect(); } renderData = () => { console.log("rendered queue", this.state.queue); if (this.state.queue === undefined) { return null; } return this.state.queue.map((task, index) => ()); }; render() { return ( {task} {index === 0 && this.state.status === "working" && ( )}); } } export default App;{this.renderData()} Instruction: {this.state.instruction}
I want the webpage to refresh immediately when new data is received. I've added a callback function to setState, but it still doesn't work.
When using socket.io in your application, you may experience delays in updating status after receiving data due to a number of factors. For example, the asynchronous nature of socket.io, state management issues, event handling, React component life cycle, etc.