code: function modifyOutRules(rules) {
  	for (let i = 0; i < rules.length; ++i) {
  		if (rules[i].test) {
  			switch ('' + rules[i].test) {
  				// Images
  				case '/\\.(png|jpe?g|gif)$/':
  					modifyOutRule(rules[i], 'images');
  					break;
  				// Fonts
  				case '/\\.(woff2?|ttf|eot|svg|otf)$/':
  					modifyOutRule(rules[i], 'fonts');
  					break;
  				default:
  
  			}
  		}
  	}
  }
docs: Modify the rules of output directories.
  
  @param  {Array} rules The rules.