react-native/scripts/testing-utils.js

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @format
 */

'use strict';

const {exec} = require('shelljs');
const os = require('os');
const {spawn} = require('node:child_process');

/*
 * Android related utils - leverages android tooling
 */

// this code is taken from the CLI repo, slightly readapted to our needs
// here's the reference folder:
// https://github.com/react-native-community/cli/blob/main/packages/cli-platform-android/src/commands/runAndroid

const emulatorCommand = process.env.ANDROID_HOME
  ? `${process.env.ANDROID_HOME}/emulator/emulator`
  : 'emulator';

const getEmulators = () => {
  const emulatorsOutput = exec(`${emulatorCommand} -list-avds`).stdout;
  return emulatorsOutput.split(os.EOL).filter(name => name !== '');
};

const launchEmulator = emulatorName => {
  // we need both options 'cause reasons:
  // from docs: "When using the detached option to start a long-running process, the process will not stay running in the background after the parent exits unless it is provided with a stdio configuration that is not connected to the parent. If the parent's stdio is inherited, the child will remain attached to the controlling terminal."
  // here: https://nodejs.org/api/child_process.html#optionsdetached

  const cp = spawn(emulatorCommand, [`@${emulatorName}`], {
    detached: true,
    stdio: 'ignore',
  });

  cp.unref();
};

function tryLaunchEmulator() {
  const emulators = getEmulators();
  if (emulators.length > 0) {
    try {
      launchEmulator(emulators[0]);

      return {success: true};
    } catch (error) {
      return {success: false, error};
    }
  }
  return {
    success: false,
    error: 'No emulators found as an output of `emulator -list-avds`',
  };
}

function launchAndroidEmulator() {
  const result = tryLaunchEmulator();
  if (result.success) {
    console.info('Successfully launched emulator.');
  } else {
    console.error(`Failed to launch emulator. Reason: ${result.error || ''}.`);
    console.warn(
      'Please launch an emulator manually or connect a device. Otherwise app may fail to launch.',
    );
  }
}

/*
 * iOS related utils - leverages xcodebuild
 */

/*
 * Metro related utils
 */

// inspired by CLI again https://github.com/react-native-community/cli/blob/main/packages/cli-tools/src/isPackagerRunning.ts

function isPackagerRunning(
  packagerPort = process.env.RCT_METRO_PORT || '8081',
) {
  try {
    const status = exec(`curl http://localhost:${packagerPort}/status`, {
      silent: true,
    }).stdout;

    return status === 'packager-status:running' ? 'running' : 'unrecognized';
  } catch (_error) {
    return 'not_running';
  }
}

// this is a very limited implementation of how this should work
function launchPackagerInSeparateWindow(folderPath) {
  const command = `tell application "Terminal" to do script "cd ${folderPath} && yarn start"`;
  exec(`osascript -e '${command}'`);
}

module.exports = {
  launchAndroidEmulator,
  isPackagerRunning,
  launchPackagerInSeparateWindow,
};