URL Parser Exercise in JS

urlparser.js

//Parse and extract data from a string like: param1=111&param2=222&param3=333
const parseQryStr = (url)=>{

  //Match xxx=yyy
  const paramRegex = '[a-zA-Z0-9]=[a-zA-Z0-9]';

  //Split the params.
  const params = url.split('&');

  //Extract the variables if match with the format.
  let values = {};

  params.forEach(param=>{
    
    if (param.match(paramRegex)){
      const parts = param.split('=');
      values[parts[0]] = parts[1];
    }

  });

  return values;

}

//Parse and extract data from a string like: /:version/api/:collecton/:id
const parseBySlash = (format,url)=>{

  //Variable format :xxxxx.
  const varRegex = '^:[a-zA-Z0-9]';

  //Split by format and url.
  const fmtChunks = format.split('/');
  const urlChunks = url.split('/');

  //If the format not match.
  if (!(urlChunks.length >= fmtChunks.length))
    throw new Error('Url format error');

  //Extract the values and match with format.
  let values = {};
  
  fmtChunks.forEach((fmt,i)=>{

    if (fmt.match(varRegex)){

      const atrib   = fmt.replace(':','');
      values[atrib] = urlChunks[i];

    }

  });

  return values;

}

//Receive the url and format and parse it.
const parse = (format,url)=>{

  const parts = url.split('?');

  //If the url have two sections, merge it.
  return (parts.length > 1) 
    ? {...parseBySlash(format,parts[0]),...parseQryStr(parts[1])}
    : parseBySlash(format,url);
  
}

//TESTING
let format = '/:version/api/:collecton/:id';
let url1   = '/6/api/listings/3?sort=desc&limit=10';
let url2   = '/6/api/listings/3';
let url3   = 'sort=desc&limit=10';

let tmp = parse(format,url3);
console.log(tmp);