Async spawn

import colors from 'colors';
import { spawn } from 'child_process';

function asyncSpawn(command, stdout = true, stderr = true) {
  const [cmd, ...args] = command.split(' ');
  return new Promise((resolve, reject) => {
    const child = spawn(cmd, args, { env });
    if (stdout) {
      child.stdout.on('data', buffer => {
        process.stdout.write(colors.white(buffer));
      });
    } else {
      child.stdout.on('data', buffer => {
        process.stdout.write(colors.white('.'));
      });
    }

    if (stderr) {
      child.stderr.on('data', buffer => {
        process.stdout.write(colors.blue(buffer));
      });
    } else {
      child.stdout.on('data', buffer => {
        process.stdout.write(colors.white('.'));
      });
    }

    child.on('close', code => {
      if (code > 0) {
        return reject();
      }

      return resolve();
    });

    child.on('error', err => {
      error('Failed to start child process.' + err);
      return reject();
    });

    return child;
  });
}

function success(...messages) {
  messages.forEach(msg => console.log('\n', colors.green.bold(msg), '\n\n'));
}

function error(...messages) {
  messages.forEach(msg => console.error('\n', colors.red.bold(msg), '\n\n'));
}

function warn(...messages) {
  messages.forEach(msg => console.warn('\n', colors.yellow.bold(msg), '\n\n'));
}

async function runBuild() {
  console.log(colors.white.underline('Building project...'));
  const command = 'cross-env babel-node ./node_modules/webpack/bin/webpack --progress';
  try {
    await asyncSpawn(command);
    success(`Web assets have been successfully generated.`);
  } catch (e) {
    error('Could not successfully build.', e);
  }
}