docs: function setOutProperty(key, options) {
  	if (options[key]) {
  		// Directory
  		let directory = (
  			typeof options[key] === 'string' && options[key]
  			||
  			!Array.isArray(options[key]) && options[key].directory
  		);
  		if (directory) {
  			Config.out[key].directory = '' + directory;
  		}
  		// Extensions
  		let extensions = (
  			Array.isArray(options[key]) && options[key]
  			||
  			Array.isArray(options[key].extensions) && options[key].extensions
  		);
  		if (extensions) {
  			for (let k in Config.out) {
  				if (Config.out.hasOwnProperty(k)) {
  					Config.out[k].extensions = arraySubtraction(
  						Config.out[k].extensions,
  						extensions
  					);
  				}
  			}
  			Config.out[key].extensions =
  				Config.out[key].extensions.concat(extensions)
  			;
  		}
  	}
  }