react-scripts.js

#!/usr/bin/env node
/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

'use strict';

const spawn = require('react-dev-utils/crossSpawn');
const script = process.argv[2];
const args = process.argv.slice(3);

switch (script) {
  case 'build':
  case 'eject':
  case 'start':
  case 'test': {
    const nodeOptions = getNodeOptionsIfPresent(script);
    const result = spawn.sync(
      'node',
      nodeOptions
        .concat([require.resolve('../scripts/' + script)])
        .concat(args),
      { stdio: 'inherit' }
    );
    if (result.signal) {
      if (result.signal === 'SIGKILL') {
        console.log(
          'The build failed because the process exited too early. ' +
            'This probably means the system ran out of memory or someone called ' +
            '`kill -9` on the process.'
        );
      } else if (result.signal === 'SIGTERM') {
        console.log(
          'The build failed because the process exited too early. ' +
            'Someone might have called `kill` or `killall`, or the system could ' +
            'be shutting down.'
        );
      }
      process.exit(1);
    }
    process.exit(result.status);
    break;
  }
  default:
    console.log('Unknown script "' + script + '".');
    console.log('Perhaps you need to update react-scripts?');
    console.log(
      'See: https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#updating-to-new-releases'
    );
    break;
}

function getNodeOptionsIfPresent(script) {
  const nameOne = 'NODE_COMMAND_LINE';
  const nameTwo = `${nameOne}_${script.toUpperCase()}`;
  const { readFileSync } = require('fs');
  const { parse } = require('dotenv');
  const path = '.env';
  const encoding = 'utf8';
  const getArgList = val => {
    return val.split('--').filter(v => v !== '').map(v => `--${v}`);
  };
  let nodeOptions = [];
  try {
    const parsedObj = parse(readFileSync(path, { encoding: encoding }));
    nodeOptions = Object.entries(parsedObj).reduce((lst, [key, val]) => {
      if (key === nameTwo) {
        lst = getArgList(val);
      } else if (key === nameOne && lst.length === 0) {
        lst = getArgList(val);
      }
      return lst;
    }, []);
  } catch (e) {
    // File does not exit or could not be read
  }
  return nodeOptions;
}