auto mock response via request points.

mocker.js

#!/usr/bin/env node

// websocketd --port 8058 ./mocker.js
const querystring = require('querystring');
const qs = process.env?.QUERY_STRING.replace('QUERY_STRING=', '');

const qsObj = querystring.parse(qs);

process.stdin.resume();
process.stdin.setEncoding('utf8');

// Receive data from WebSocket - STDIN
process.stdin.on('data', function (req) {
  // Send data to WebSocket client - STDOUT
  const data = JSON.parse(req.trim());

  startInterval(() => {
    const values = data.points.map(item => {
      const value = item.includes('_YX') ? Math.round(Math.random()) : Math.random() * 100;
      return { point: item, value };
    });
    process.stdout.write(JSON.stringify({ now: +new Date(), values, type: "GetNowValue" }) + '\n');
  }, 5000);
})

function startInterval(callback, ms) {
  callback();
  return setInterval(callback, ms);
}