parcel-bundler/lib/Server.js

<p align="center"> <a href="https://parceljs.org/" target="_blank"> <img alt="Parcel" src="https://user-images.githubusercontent.com/19409/31321658-f6aed0f2-ac3d-11e7-8100-1587e676e0ec.png" width="749"> </a> </p>

'use strict';

let serve = (() => {
  var _ref = _asyncToGenerator(function* (bundler, port) {
    let freePort = yield getPort({ port });
    let server = http.createServer(middleware(bundler)).listen(freePort);

    return new Promise(function (resolve, reject) {
      server.on('error', function (err) {
        bundler.logger.error(new Error(serverErrors(err, server.address().port)));
        reject(err);
      });

      server.once('listening', function () {
        let addon = server.address().port !== port ? `- ${bundler.logger.chalk.red(`configured port ${port} could not be used.`)}` : '';
        bundler.logger.persistent(`Server running at ${bundler.logger.chalk.cyan(`http://localhost:${server.address().port}`)} ${addon}`);

        resolve(server);
      });
    });
  });

  return function serve(_x, _x2) {
    return _ref.apply(this, arguments);
  };
})();

function _asyncToGenerator(fn) { return function () { var gen = fn.apply(this, arguments); return new Promise(function (resolve, reject) { function step(key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { return Promise.resolve(value).then(function (value) { step("next", value); }, function (err) { step("throw", err); }); } } return step("next"); }); }; }

const http = require('http');
const serveStatic = require('serve-static');
const getPort = require('get-port');
const serverErrors = require('./utils/customErrors').serverErrors;

function middleware(bundler) {
  const serve = serveStatic(bundler.options.outDir, { index: false });

  return function (req, res, next) {
    // Wait for the bundler to finish bundling if needed
    if (bundler.pending) {
      bundler.once('bundled', respond);
    } else {
      respond();
    }

    function respond() {
      if (bundler.errored) {
        return send500();
      } else if (!req.url.startsWith(bundler.options.publicURL)) {
        // If the URL doesn't start with the public path, send the main HTML bundle
        return sendIndex();
      } else {
        // Otherwise, serve the file from the dist folder
        req.url = req.url.slice(bundler.options.publicURL.length);
        return serve(req, res, send404);
      }
    }

    function sendIndex() {
      // If the main asset is an HTML file, serve it
      if (bundler.mainAsset.type === 'html') {
        req.url = `/${bundler.mainAsset.generateBundleName()}`;
        serve(req, res, send404);
      } else {
        send404();
      }
    }

    function send500() {
      res.setHeader('Content-Type', 'text/plain; charset=utf-8');
      res.writeHead(500);
      res.end('🚨 Build error, check the console for details.');
    }

    function send404() {
      if (next) {
        return next();
      }

      res.writeHead(404);
      res.end();
    }
  };
}

exports.middleware = middleware;
exports.serve = serve;