code: function _shellBundle({
    src = 'app/main.js',
    dest = 'dist',
    baseName = 'build',
    ignoreVendors = false,
    onlyVendors = false
  } = {}, jspmConfig, useSourcemaps = false) {
    // Get dependencies from jspm configurations
    const vendors = Object.keys(jspmConfig.dependencies)
  
    // Commands to prepare the shell to bundle with jspm
    let arithmetic = ''
    let opt = '--minify --skip-source-maps'
    let source = src
  
    // Only minify and keep sourcemaps
    if (useSourcemaps) {
      opt = '--minify'
    }
  
    // Make string to ignore vendors in bundle app.
    if (ignoreVendors) {
      arithmetic = _vendorsList(vendors, true)
    }
  
    // Make string to include only vendors in bundle dep and change source
    // command.
    if (onlyVendors) {
      source = vendors[0]
      arithmetic = _vendorsList(vendors, false)
    }
  
    // Return shell command to bundle
    return [
      `jspm bundle ${source} ${arithmetic} ${dest}/${baseName}.js ${opt}`
    ]
  }
docs: HELPER FUNCTIONS 
  Prepare shell comand for jspm bundle
  @param {Object} - An options object with this properties:
  {
  Source path
  src: 'app/main.js',
  
  Destination path
  dest: 'dest/path',
  
  Name of the output file without extension
  baseName: 'build',
  
  Make arithmetic to only bundle app files (no include jspm dependencies)
  ignoreVendors: false,
  
  Make source and arithmetic to bundle only dependencies
  onlyVendors: false
  }
  @param {Object} jspmConfig - jspm object extracted from package.json of main
  project
  @param {boolean} useSourcemaps - indicate if use sourcemaps