poly-live-serve.js

'use strict';

const browserSync = require('browser-sync').create();
const portfinder = require('portfinder');
const {spawn} = require('child_process');

const COMPONENT_PATH = process.env.npm_package_name;
const browserSyncConfig = {
  open: false,
  notify: false,
  ghostMode: false,
  reloadOnRestart: true,
  ui: false,
  proxy: `localhost:{{port}}/components/${COMPONENT_PATH}/`,
  files: ['**/*.{js,html}']
};

const startServer = (port) => {
  const polymerCliParams = ['serve', '--npm', '-p', port];
  const polymerServe = spawn('polymer', polymerCliParams);

  polymerServe.stdout.on('data', (data) => {
    console.log(`${data}`);
    browserSync.init(getServerConfig(port));
  });

  polymerServe.stderr.on('data', (data) => {
    console.log(`Error: ${data}`);
  });

  polymerServe.on('close', (code) => {
    console.log(`child process exited with code ${code}`);
  });
};

const getServerConfig = (port) => {
  return JSON.parse(
    JSON.stringify(browserSyncConfig)
      .replace(/{{port}}/g, port)
    );
};

const serve = () => {
  portfinder.getPortPromise()
    .then(startServer)
    .catch((error) => console.error(error));
};

serve();