How to use the child_process.promise function in child_process

async function listSimulatorsAsync() {
  try {
    var output = await child_process.promise.exec('xcrun simctl list devices');
  } catch (e) {
    throw SimulatorNotAvailable(e);
  }

  var lines = output.split("\n");
  var devices = [];

  var runtime;
  for (var line of lines) {
    var m = line.match(/^-- ([^-]+) --$/);
    if (m) {
      runtime = m[1];
      if (runtime.match(/^Unavailable: /)) {
        runtime = undefined;
      }
    }

var ok = yield urlUtil.testUrlAsync(httpUrl);
      } catch (e) {
        throw CommandError('RUN_EXP_START_FIRST', env, 'You may need to run `exp start` to get a URL\n' + e.message);
      } finally {
        simpleSpinner.stop();
      }
      log('OK.');
    }

    log('Opening article in web simulator...');
    console.log();
    console.log(crayon.underline(appetizeUrl));
    console.log();

    if (process.platform === 'darwin') {
      var result = yield child_process.promise.exec('open ' + appetizeUrl, { stdio: 'inherit' });
    } else {
      log.error('Sorry, opening the URL for the web simulator automatically only works on Mac for now.');
    }

    return appetizeUrl;
  }) };
//# sourceMappingURL=../sourcemaps/commands/web.js.map

var ok = await urlUtil.testUrlAsync(httpUrl);
      } catch (e) {
        throw CommandError('RUN_EXP_START_FIRST', env, "You may need to run `exp start` to get a URL\n" + e.message);
      } finally {
        simpleSpinner.stop();
      }
      log("OK.");
    }

    log("Opening article in web simulator...");
    console.log();
    console.log(crayon.underline(appetizeUrl));
    console.log();

    if (process.platform === 'darwin') {
      var result = await child_process.promise.exec("open " + appetizeUrl, {stdio: 'inherit'});
    } else {
      log.error("Sorry, opening the URL for the web simulator automatically only works on Mac for now.");
    }

    return appetizeUrl;

  },
};

var listSimulatorsAsync = _asyncToGenerator(function* () {
  try {
    var output = yield child_process.promise.exec('xcrun simctl list devices');
  } catch (e) {
    throw SimulatorNotAvailable(e);
  }

  var lines = output.split('\n');
  var devices = [];

  var runtime;
  for (var line of lines) {
    var m = line.match(/^-- ([^-]+) --$/);
    if (m) {
      runtime = m[1];
      if (runtime.match(/^Unavailable: /)) {
        runtime = undefined;
      }
    }

async function latestExpVersionAsync() {
  var packageName = await jsonFile(path.join(__dirname, '..', 'package.json')).getAsync('name');
  var version_ = await child_process.promise.exec('npm view ' + packageName + ' version');
  return version_.trim();

}

async function openUrlOnSimulatorAsync(url) {
  return child_process.promise.exec('xcrun simctl openurl booted ' + JSON.stringify(url));
}

var latestExpVersionAsync = _asyncToGenerator(function* () {
  var packageName = yield jsonFile(path.join(__dirname, '..', 'package.json')).getAsync('name');
  var version_ = yield child_process.promise.exec('npm view ' + packageName + ' version');
  return version_.trim();
});