create-js-app-scripts/build/start.js

'use strict';

/* eslint-disable no-console */
// set environment to development
process.env.NODE_ENV = 'development';

const fs = require('fs');
const Environment = require('./environment');
const Logger = require('./logger');

const env = new Environment(fs.realpathSync(process.cwd()), undefined, new Logger());

process.on('SIGINT', () => {
  env.stop();
});

env.start().catch(e => {
  console.log(e);
  process.exit(1);
});