code: function isBuiltinPreset(name) {
  	var isNpmPresetName = /^(?:babel-preset-)/;
  	var availablePresets = babel.availablePresets || {};
  
  	var shorthand = isNpmPresetName.test(name) ?
  		name.replace("babel-preset-", "") :
  		name;
  
  	return !!availablePresets[shorthand];
  }
docs: Whether the preset is built in babel-standalone
  
  @param {string} name A preset path
  @return {boolean} `true` if preset is builtin, `false` otherwise
  
  Babel presets can be set using the following variations:
  
  1) the npm preset name, which by convention starts with `babel-preset-`
  2) A shorthand name, which is the npm name without the prefix
  3) A path to where the preset is defined
  
  babel-standalone registers the builtin presets using the shorthand version.