Prompt for user input.
https://www.youtube.com/watch?v=NIGhjrWLWBo
shows how to do this for C++. For Node.js, this is taken right from the docs (and it works):
'use strict';
console.log('Hello world');
const readline = require('readline');
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout
});
rl.question('Press enter to continue...', (answer) => {
rl.close(); /* discard the answer */
});