parseQueryString

var parseString = function(/*string*/string) { /* array of strings */
  return string.split("&");
}

var parseKeyValueString = function(/*array*/stringsArray) {

  return stringsArray.reduce(function(subArray, keyValueString) {
    var subArrayKeyValue = keyValueString.split("=")
    return subArray.concat([subArrayKeyValue]);
  },[])
}

var parseQueryString = function(/*list<pair<string, string>>*/ array) { /* map of key to value */
  return array.reduce(function(queryMap, keyValueArray) {
    var map = (queryMap[keyValueArray[0]] = keyValueArray[1]);
    // console.log(queryMap)
    return queryMap[keyValueArray[0]] ? queryMap : map;
  }, {})
}


var queryTestString1 = "name=Timur&last_name=Meyster&[email protected]"
var queryTestString2 = "name=Timur&name=Timur&last_name=Meyster&[email protected]"
console.log(parseQueryString(parseKeyValueString(parseString(queryTestString1))));
console.log(parseQueryString(parseKeyValueString(parseString(queryTestString2))));