How to exchange variable between ReactJS and Python script

Question

I have a ReactJS application that has the following workflow:
user submit input -> send input to Python script (with python-shell npm package) for computing result -> store the returned result to firebase.
PS: The Python function couldn't be re-written in Javascript.

User submit input:

<div className="post_container">
 <div className="input">
 /* User submit the input -> compute result -> store to firebase*/
 <form>
 <input value={input} onChange={e => setInput(e.target.value)} type="text"></input>
 <button onClick={sendPost} type="submit">Submit</button>
 </form>
 </div>
</div>

A Javascript function that calls the Python file:

const computeResult = () => {
 let result;
 /* Python script has a function that computes the result */
 let python = new PythonShell('script.py');
 
 python.send(input); /* send the input to the script */
 python.on('message', function (message) {
 console.log(`Message received from Python: ${message}`);
 result = message; /* receive the computed result from the script */
 });
 python.end(function (err,code,signal) {
 if (err) throw err;
 console.log('The exit code was: ' + code);
 console.log('The exit signal was: ' + signal);
 console.log('finished');
 });
 return result;
}

Store the result to firebase:

const sendPost = async(e) => {
 e.preventDefault();
 /* Compute the result by calling computeResult()*/
 let result = await computeResult();
 
 /* Store the result to the firebase */
 db.collection('posts').add({
 time: firebase.firestore.FieldValue.serverTimestamp(), 
 result: result
 })
 setInput(''); 
}

The full code is as shown below:

import React, { useEffect, useState } from 'react';
import { db } from './firebase';
import firebase from 'firebase';
import {PythonShell} from 'python-shell';
function Post() {
 const [input, setInput] = useState('');
 /* A function that calls Python script */
 const computeResult = () => {
 let result;
 /* Python script has a function that computes the result */
 let python = new PythonShell('script.py');
 
 python.send(input); /* send the input to the script */
 python.on('message', function (message) {
 console.log(`Message received from Python: ${message}`);
 result = message; /* receive the computed result from the script */
 });
 python.end(function (err,code,signal) {
 if (err) throw err;
 console.log('The exit code was: ' + code);
 console.log('The exit signal was: ' + signal);
 console.log('finished');
 });
 return result;
 }
 const sendPost = async(e) => {
 e.preventDefault();
 /* Compute the result by calling computeResult()*/
 let result = await computeResult();
 
 /* Store the result to the firebase */
 db.collection('posts').add({
 time: firebase.firestore.FieldValue.serverTimestamp(), 
 result: result
 })
 setInput(''); 
 }
 return (
 <div className="post_container">
 <div className="input">
 /* User submit the input -> compute result -> store to firebase*/
 <form>
 <input value={input} onChange={e => setInput(e.target.value)} type="text"></input>
 <button onClick={sendPost} type="submit">Submit</button>
 </form>
 </div>
 </div>
 )
}
export default Post

When I run npm start, no error message displayed in the terminal. Instead the error message occurs in localhost:3000. I've no clue how I can solve this error.

TypeError: The "original" argument must be of type Function
promisify
node_modules/util/util.js:601
 598 | var kCustomPromisifiedSymbol = typeof Symbol !== 'undefined' ? Symbol('util.promisify.custom') : undefined;
 599 | 
 600 | exports.promisify = function promisify(original) {
> 601 | if (typeof original !== 'function')
 602 | throw new TypeError('The "original" argument must be of type Function');
 603 | 
 604 | if (kCustomPromisifiedSymbol && original[kCustomPromisifiedSymbol]) {

• Alexander Nied: Is this a website? Or a node application that is somehow running on a user's machine?
• dan webb: Does this help? stackoverflow.com/questions/61063018/…
• Jimm: @AlexanderNied An application running on a user's machine
• Jimm: @danwebb Let me go check it out. Be right back
• Jimm: @danwebb Doesn't help. Still the same error message. I just edited the post regarding the error message

Answer 1

It will be better first you take the user input seperately on your node app and then call python script.

Follow this link to know working of python with node.

https://stackoverflow.com/a/54217251/8884612