get_jest.js

/**
 * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */

import type {Path} from 'types/Config';

import path from 'path';
import chalk from 'chalk';
import fs from 'graceful-fs';
// eslint-disable-next-line import/default
import jest from '../jest';

export default function getJest(packageRoot: Path) {
  const packageJSONPath = path.join(packageRoot, 'package.json');
  const binPath = path.join(packageRoot, 'node_modules/jest-cli');
  if (fs.existsSync(binPath)) {
    /* $FlowFixMe */
    return require(binPath);
  } else {
    // Check if Jest is specified in `package.json` but not installed.
    if (fs.existsSync(packageJSONPath)) {
      /* $FlowFixMe */
      const packageJSON = require(packageJSONPath);
      const dependencies = packageJSON.dependencies;
      const devDependencies = packageJSON.devDependencies;
      if (
        (dependencies && dependencies['jest-cli']) ||
        (devDependencies && devDependencies['jest-cli'])
      ) {
        process.on('exit', () =>
          console.log(
            chalk.red(
              'Please run `npm install` to use the version of Jest intended ' +
                'for this project.',
            ),
          ),
        );
      }
    }
    return jest;
  }
}