proxy.config.js

const fs = require('fs');

const targets = [
  'https://api.trains-master.hosted.allegro.ai',            // 1
];

const PROXY_CONFIG = {
  '^/version.json$': {
    bypass: (req, res, proxyOptions) => {
      let url;
      if (req.url === '/version.json') {
        url = 'src/version.json';
      } else if (req.url === '/configuration.json') {
        url = 'src/configuration.json';
      } else if (req.url === '/onboarding.json') {
        url = 'src/onboarding.json';
      } else {
        return  req.url;
      }

      const ver = fs.readFileSync(url);
      res.writeHead(200, {
        'Content-Length': ver.length,
        'Content-Type': 'application/json'
      });
      res.end(ver);
      return true;
    }
  }
};

targets.forEach((target, i) => {
  const path = `/service/${i+1}/api`;
  PROXY_CONFIG[path + '/*'] = {
    target: target,
    secure: false,
    changeOrigin: true,
    pathRewrite: {
      [path]: ''
    }
  };
});

module.exports = PROXY_CONFIG;