A function that spawns a new process using the given command, logging the stdout and stderr.

sh.js

const cp = require('child_process')

/**
 * A function that spawns a new process using the given command, logging the stdout and stderr.
 *
 * @param {String} command
 * @param {Array} args
 * @return {Promise}
 * @example
 *
 *      sh('ping', ['-c', '3', '8.8.8.8'])
 *        .then(console.log)
 *        .catch(console.error)
 */
function sh (command, args = []) {
  const logString = msg => console.log(`${msg}`)
  const childProcess = cp.spawn(command, args)
  const formattedArgs = args.length ? ` ${args.join(' ')}` : ''
  const params = `$ ${command}${formattedArgs}`

  logString(params)

  return new Promise((resolve, reject) => {
    childProcess.stdout.on('data', logString)
    childProcess.stderr.on('data', logString)

    childProcess.on('error', reject)

    childProcess.on('exit', (code, signal) => {
      const message = `Child process exited with code ${code}`

      if (code !== 0) {
        return reject(new Error(message))
      }

      return resolve({ code, signal })
    })
  })
}

module.exports = sh