// ./index.js
const spawn = require("child_process").spawn;
const process = spawn("python", ["./test.py"]);
process.stdout.on("data", data => {
  console.log(data.toString());
});
process.stderr.on("data", data => {
  console.log("ERR");
  console.log(data.toString());
});// ./test.py
print("Hello world")$ node index.js
ERR
Python