How do I get data returned from the python script into node js?

Question

I am trying to run a python script that uses HC-SR04 sensors to monitor distance and returns the distance measured back to my NodeJS code. If I run the python script by itself it seems to be printing out the correct outputs. But when I console log it in NodeJS nothing returns?

below is the python script

import sys, json
import RPi.GPIO as GPIO
import time


print('test')

GPIO.setmode(GPIO.BCM)

#set GPIO Pins
GPIO_TRIGGER = 22
GPIO_ECHO = 27

#set either in or out
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN)


def distance():
    #set trigger high
    GPIO.output(GPIO_TRIGGER, True)

    #set trigger low
    time.sleep(0.00001)
    GPIO.output(GPIO_TRIGGER, False)

    StartTime = time.time()
    StopTime = time.time()

    while GPIO.input(GPIO_ECHO) == 0:
        StartTime = time.time()

    while GPIO.input(GPIO_ECHO) == 1:
        StopTime = time.time()


    TimeElapsed = StopTime - StartTime

    distance = (TimeElapsed * 34300) / 2

    return distance


try:
    while True:
        data = distance()
        print(data)
        time.sleep(1)

except KeyboardInterrupt:
    print("stopped by user")
    GPIO.cleanup()

Below is the app.js

var express = require('express');
var app = express();
var path = require('path');
process.env.PYTHONPATH = '/usr/lib/python3';
console.log(process.env.PYTHONPATH)


const spawn = require('child_process').spawn;


// set the view engine to ejs
app.set('view engine', 'ejs');
app.set('views', path.join(__dirname, '/views'));
app.use(express.static(__dirname + '/'));
// use res.render to load up an ejs view file
// index page
app.get('/', function(req, res) {
  res.render('index.ejs');
});

//make data string as python does not do json
//let stringifiedData = JSON.stringify(data);
//call python process
const py = spawn('/usr/bin/python3', ['sensors.py']);

var resultString = ' ';

py.stdout.on('data', function (data) {
  console.log('Data on');
  resultString += data;
  console.log(resultString);
});

py.stdout.on('end', function (){
  let resultData = resultString;
  console.log(resultString);
});

py.on('close', (code) => {
  console.log(`child process close all stdio with code ${code}`);
});


app.listen(80);
console.log('Server is listening on port 80');
console.log('Server is running!');

So yeah that's about it please help.