text: /** Copyright 2018 Novartis Institutes for BioMedical Research Inc.
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. */
  
  const fs = require('fs');
  const path = require('path');
  const paths = require('./paths');
  
  // Make sure that including paths.js after env.js will read .env variables.
  delete require.cache[require.resolve('./paths')];
  
  const NODE_ENV = process.env.NODE_ENV;
  if (!NODE_ENV) {
    throw new Error(
      'The NODE_ENV environment variable is required but was not specified.'
    );
  }
  
  // https://github.com/bkeepers/dotenv#what-other-env-files-can-i-use
  const dotenvFiles = [
    `${paths.dotenv}.${NODE_ENV}.local`,
    `${paths.dotenv}.${NODE_ENV}`,
    // Don't include `.env.local` for `test` environment
    // since normally you expect tests to produce the same
    // results for everyone
    NODE_ENV !== 'test' && `${paths.dotenv}.local`,
    paths.dotenv
  ].filter(Boolean);
  
  // Load environment variables from .env* files. Suppress warnings using silent
  // if this file is missing. dotenv will never modify any environment variables
  // that have already been set.  Variable expansion is supported in .env files.
  // https://github.com/motdotla/dotenv
  // https://github.com/motdotla/dotenv-expand
  dotenvFiles.forEach(dotenvFile => {
    if (fs.existsSync(dotenvFile)) {
      require('dotenv-expand')(
        require('dotenv').config({
          path: dotenvFile
        })
      );
    }
  });
  
  // We support resolving modules according to `NODE_PATH`.
  // This lets you use absolute paths in imports inside large monorepos:
  // https://github.com/facebook/create-react-app/issues/253.
  // It works similar to `NODE_PATH` in Node itself:
  // https://nodejs.org/api/modules.html#modules_loading_from_the_global_folders
  // Note that unlike in Node, only *relative* paths from `NODE_PATH` are honored.
  // Otherwise, we risk importing Node.js core modules into an app instead of Webpack shims.
  // https://github.com/facebook/create-react-app/issues/1023#issuecomment-265344421
  // We also resolve them to make sure all tools using them work consistently.
  const appDirectory = fs.realpathSync(process.cwd());
  process.env.NODE_PATH = (process.env.NODE_PATH || '')
    .split(path.delimiter)
    .filter(folder => folder && !path.isAbsolute(folder))
    .map(folder => path.resolve(appDirectory, folder))
    .join(path.delimiter);
  
  // Grab NODE_ENV and REACT_APP_* environment variables and prepare them to be
  // injected into the application via DefinePlugin in Webpack configuration.
  const REACT_APP = /^REACT_APP_/i;
  
  function getClientEnvironment(publicUrl) {
    const raw = Object.keys(process.env)
      .filter(key => REACT_APP.test(key))
      .reduce(
        (env, key) => {
          env[key] = process.env[key];
          return env;
        },
        {
          // Useful for determining whether we’re running in production mode.
          // Most importantly, it switches React into the correct mode.
          NODE_ENV: process.env.NODE_ENV || 'development',
          // Useful for resolving the correct path to static assets in `public`.
          // For example, <img src={process.env.PUBLIC_URL + '/img/logo.png'} />.
          // This should only be used as an escape hatch. Normally you would put
          // images into the `src` and `import` them in code to get their paths.
          PUBLIC_URL: publicUrl
        }
      );
    // Stringify all values so we can feed into Webpack DefinePlugin
    const stringified = {
      'process.env': Object.keys(raw).reduce((env, key) => {
        env[key] = JSON.stringify(raw[key]);
        return env;
      }, {})
    };
  
    return { raw, stringified };
  }
  
  module.exports = getClientEnvironment;
  