export default sort => {
  let key, ascDesc;
  switch(typeof sort) {
  case 'object': {
    key = Object.keys(sort).pop(); 
    ascDesc = sort[key]; 
    break;
  }
  case 'string': {
    const parts = sort.split(':'); 
    key = parts[0]; 
    ascDesc = parts[1]; 
    break; 
  }
  default: break; 
  }
  return `$sort[${key}]=${ascDesc}`; 
};