Socket.io sending messages - client

import React, {Component} from 'react';
import socketIOClient from 'socket.io-client';

class Personal extends Component {
    constructor(props) {
        super(props);
        this.state = {
            endpoint: 'http://127.0.0.1:3001',
            messages: [],
            ourMessage: ''
        };

        this.socket = socketIOClient(this.state.endpoint);
        this.onWrite = this.onWrite.bind(this);
        this.sendMessage = this.sendMessage.bind(this);
    }

    componentWillMount() {
        this.socket.on('server_message', data => {
            let messages = this.state.messages;
            messages.push(data);
            this.setState({messages: messages});
        });
    }

    componentWillUnmount() {
        this.socket.disconnect();
    }

    onWrite(e) {
        this.setState({ourMessage: e.target.value});
    }

    sendMessage(e) {
        e.preventDefault;
        this.socket.emit('client_message', this.state.ourMessage);
        this.setState({ourMessage: ''})
    }

    render() {
        const style = {'marginTop': '50px'};
        const messages = this.state.messages;
        return (
            <div style={style}>
                <div>
                    <input type='text' onChange={this.onWrite} value={this.state.ourMessage}/>
                    <input type='button' onClick={this.sendMessage} value='send'/>
                </div>
                Messages:
                {messages.map((value, index) => {
                    return <div key={index}>{index}. {value}</div>;
                })}
            </div>
        );
    }
}

export default Personal;