Function install

src/install.js:163–219

(root, useYarn, dependencies, verbose, isOnline, isDevDependencies)

}

function install(root, useYarn, dependencies, verbose, isOnline, isDevDependencies) {
  return new Promise((resolve, reject) => {
    let command;
    let args;
    if (useYarn) {
      command = 'yarnpkg';
      //args = ['add', '--exact']
      args = ['add'];
      if (!isOnline) {
        args.push('--offline');
      }
      if (isDevDependencies) {
        args.push('--dev');
      }
      [].push.apply(args, dependencies);

      // Explicitly set cwd() to work around issues like
      // https://github.com/facebook/create-react-app/issues/3326.
      // Unfortunately we can only do this for Yarn because npm support for
      // equivalent --prefix flag doesn't help with this issue.
      // This is why for npm, we run checkThatNpmCanReadCwd() early instead.
      args.push('--cwd');
      args.push(root);

      if (!isOnline) {
        console.log(chalk.yellow('You appear to be offline.'));
        console.log(chalk.yellow('Falling back to the local Yarn cache.'));
        console.log();
      }
    } else {
      command = 'npm';
      args = ['install', '--loglevel', 'error'];
      if (isDevDependencies) {
        args.push('--save-dev');
      } else {
        args.push('--save');
      }

      [].push.apply(args, dependencies);
    }

    if (verbose) {
      args.push('--verbose');
    }

    const child = spawn(command, args, { stdio: 'inherit' });
    child.on('close', (code) => {
      if (code !== 0) {
        reject({
          command: `${command} ${args.join(' ')}`,
        });
        return;
      }
      resolve();
    });
  });
}