code: function ratio(options) {
  	const { width, height } = options;
  
  	if ((width || height) && !(width && height)) {
  		if (width) {
  			options.height = width;
  		}
  		if (height) {
  			options.width = height;
  		}
  	}
  
  	return options;
  }
docs: Determine the correct "opposite" dimension in case only one of width or height is provided
  
  @param   {object} options
  @returns {object} options