React Native with socket.io doesn't work

i create simple socket.io server and react native project and tested, but socket.io on React Native doesn't work at all. i printed "socket.io-client" on console and it's loaded well, and i made simple HTML file with using socket.io, it works, but only React Native doesn't work. i'm using React native 0.26.2, and socket.io 1.4.6.

this is my server code:

"strict mode";
const express = require('express');
const app = express();
const http = require('http').Server(app);
const io = require('socket.io')(http);

io.on('connection', (socket) => {
    console.log('user connected');
});

http.listen(3000, () => {
    console.log('server started on 3000');
});

// web testing
app.get('/', (req, res, next) => {
    res.sendFile(__dirname + '/index.html');
});

and this is rn code:

import React, { Component } from 'react';
import { AppRegistry, StyleSheet, Text, TextInput, TouchableHighlight, View } from 'react-native';

import "./userAgent"; //window.navigator.userAgent = "react-native";

const io = require('socket.io-client/socket.io');

class SocketChat extends Component {
    constructor(props) {
        super(props);
        this.socket = io('localhost:3000', { jsonp: false });
        this.state = {
            text: null
        };
    }
    ...
}

as i heard, using React native with socket.io causes ajax long polling instead of websocket, so i added 'user-agent' trick. whether it is working or not, even connection isn't established, but if i try with browser, it works well. it will be very appreciate me that tell me what should i do.

I solved this by replacing another websocket module. Socket.IO doesn't work on Android and as someone said to me, Socket.io uses node native modules internally so it should be not working after build production app.