How to use sockets to send information from javascript to python

You should determine which code is the server and which one is the client. I assume your Python code is your server. You can run a server in python using:

import socket

HOST = '0.0.0.0'
PORT = 9999    

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.bind((HOST, PORT))
    s.listen()
    conn, addr = s.accept()
    with conn:
        print('Connected by', addr)
        while True:
            data = conn.recv(1024)
            if not data:
                break
            conn.sendall(data)

And then you can connect your Nodejs client code to the server:

var net = require('net');

var HOST = '127.0.0.1';
var PORT = 9999;

var client = new net.Socket();
client.connect(PORT, HOST, function() {
  console.log('CONNECTED TO: ' + HOST + ':' + PORT);
  // Write a message to the socket as soon as the client is connected, the server will receive it as message from the client
 client.write('Message from client');

});

// Add a 'data' event handler for the client socket
// data is what the server sent to this socket
client.on('data', function(data) {
  console.log('DATA: ' + data);
  // Close the client socket completely
  client.destroy();
});

// Add a 'close' event handler for the client socket
client.on('close', function() {
  console.log('Connection closed');
});