text: // @remove-file-on-eject
  /**
   * 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 fs = require('fs');
  const chalk = require('chalk');
  const paths = require('../../config/paths');
  
  module.exports = (resolve, rootDir) => {
    // Use this instead of `paths.testsSetup` to avoid putting
    // an absolute filename into configuration after ejecting.
    const setupTestsFile = fs.existsSync(paths.testsSetup)
      ? '<rootDir>/src/setupTests.ts'
      : undefined;
  
    // TODO: I don't know if it's safe or not to just use / as path separator
    // in Jest configs. We need help from somebody with Windows to determine this.
    const config = {
      mapCoverage: true,
      collectCoverageFrom: ['src/**/*.{js,jsx,ts,tsx}'],
      setupFiles: [resolve('config/polyfills.js')],
      setupTestFrameworkScriptFile: setupTestsFile,
      moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json'],
      testMatch: [
        '<rootDir>/src/**/__tests__/**/*.ts?(x)',
        '<rootDir>/src/**/?(*.)(spec|test).ts?(x)',
      ],
      testEnvironment: 'node',
      testURL: 'http://localhost',
      transform: {
        '^.+\\.css$': resolve('config/jest/cssTransform.js'),
        '^.+\\.tsx?$': resolve('config/jest/typescriptTransform.js'),
        '^(?!.*\\.(css|json)$)': resolve('config/jest/fileTransform.js'),
      },
      transformIgnorePatterns: [
        '[/\\\\]node_modules[/\\\\].+\\.(js|jsx|ts|tsx)$',
      ],
      moduleNameMapper: {
        '^react-native$': 'react-native-web',
      },
      modulePaths: ['src/'],
      globals: {
        'ts-jest': {
          tsConfigFile: paths.appTsTestConfig,
        },
      },
    };
    if (rootDir) {
      config.rootDir = rootDir;
    }
    const overrides = Object.assign({}, require(paths.appPackageJson).jest);
    const supportedKeys = [
      'collectCoverageFrom',
      'coverageReporters',
      'coverageThreshold',
      'snapshotSerializers',
      'modulePaths',
    ];
    if (overrides) {
      supportedKeys.forEach(key => {
        if (overrides.hasOwnProperty(key)) {
          config[key] = overrides[key];
          delete overrides[key];
        }
      });
      const unsupportedKeys = Object.keys(overrides);
      if (unsupportedKeys.length) {
        console.error(
          chalk.red(
            'Out of the box, Create React App only supports overriding ' +
              'these Jest options:\n\n' +
              supportedKeys.map(key => chalk.bold('  \u2022 ' + key)).join('\n') +
              '.\n\n' +
              'These options in your package.json Jest configuration ' +
              'are not currently supported by Create React App:\n\n' +
              unsupportedKeys
                .map(key => chalk.bold('  \u2022 ' + key))
                .join('\n') +
              '\n\nIf you wish to override other Jest options, you need to ' +
              'eject from the default setup. You can do so by running ' +
              chalk.bold('npm run eject') +
              ' but remember that this is a one-way operation. ' +
              'You may also file an issue with Create React App to discuss ' +
              'supporting more options out of the box.\n'
          )
        );
        process.exit(1);
      }
    }
    return config;
  };
  