talk/scripts/start.js

"use strict";

// tslint:disable: no-console

// Do this as the first thing so that any code reading it knows the right env.
process.env.BABEL_ENV = "development";
process.env.NODE_ENV = "development";

// Makes the script crash on unhandled rejections instead of silently
// ignoring them. In the future, promise rejections that are not handled will
// terminate the Node.js process with a non-zero exit code.
process.on("unhandledRejection", err => {
  throw err;
});

// Ensure environment variables are read.
require("../config/env");

const fs = require("fs");
const chalk = require("chalk");
const webpack = require("webpack");
const WebpackDevServer = require("webpack-dev-server");
const {
  choosePort,
  createCompiler,
  prepareProxy,
  prepareUrls,
} = require("react-dev-utils/WebpackDevServerUtils");
const paths = require("../config/paths");
const config = require("../config/webpack.config.dev");
const createDevServerConfig = require("../config/webpackDevServer.config");

const PORT = parseInt(process.env.DEV_SERVER_PORT, 10) || 8080;
const HOST = process.env.HOST || "0.0.0.0";

if (process.env.HOST) {
  console.log(
    chalk.cyan(
      `Attempting to bind to HOST environment variable: ${chalk.yellow(
        chalk.bold(process.env.HOST)
      )}`
    )
  );
  console.log(
    `If this was unintentional, check that you haven't mistakenly set it in your shell.`
  );
  console.log(`Learn more here: ${chalk.yellow("http://bit.ly/2mwWSwH")}`);
  console.log();
}

// We attempt to use the default port but if it is busy, we offer the user to
// run on a different port. `choosePort()` Promise resolves to the next free port.
choosePort(HOST, PORT)
  .then(port => {
    if (port == null) {
      // We have not found a port.
      return;
    }
    const protocol = process.env.HTTPS === "true" ? "https" : "http";
    const appName = require(paths.appPackageJson).name;
    const urls = prepareUrls(protocol, HOST, port);
    // Create a webpack compiler that is configured with custom messages.
    const compiler = createCompiler(webpack, config, appName, urls);
    // Load proxy config
    const proxySetting = require(paths.appPackageJson).proxy;
    const proxyConfig = prepareProxy(proxySetting, paths.appPublic);
    // Serve webpack assets generated by the compiler over a web sever.
    const serverConfig = createDevServerConfig(
      proxyConfig,
      urls.lanUrlForConfig
    );
    const devServer = new WebpackDevServer(compiler, serverConfig);
    // Launch WebpackDevServer.
    devServer.listen(port, HOST, err => {
      if (err) {
        return console.log(err);
      }
      console.log(chalk.cyan("Starting the development server...\n"));
    });

    ["SIGINT", "SIGTERM"].forEach(function(sig) {
      process.on(sig, function() {
        devServer.close();
        process.exit();
      });
    });
  })
  .catch(err => {
    if (err && err.message) {
      console.log(err.message);
    }
    process.exit(1);
  });