nestedMapToQueryString

queryMap = {
  address: "3400 stratford",
  full_name: {
    first_name: 'Timur',
    last_name: 'Meyster'
  },
  email: '[email protected]'
  }

var turnMapToArray = function(queryMap) {
  return Object.keys(queryMap).reduce(function(arrKeyVal, key) {
    if(typeof queryMap[key] === 'object') {
      return arrKeyVal.concat([[key, turnMapToArray(queryMap[key])]]);
    } else {
      return arrKeyVal.concat([[encodeURIComponent(key), encodeURIComponent(queryMap[key])]]);
    }
  }, [])
}

var joinArrayStrings = function(arrayStr) {

  return arrayStr.reduce(function(joinedArray, arrayItem) {
    if(typeof arrayItem[1] === 'string') {
      return joinedArray.concat(arrayItem.join("="));
    } else {
      return joinedArray.concat(nestedMap(arrayItem));
    }
  }, [])
}

var nestedMap = function(arrayItem) {
  var key = arrayItem[0];
  return arrayItem[1].reduce(function(output, keyValue) {
    var nestedKey = encodeURIComponent([key, keyValue[0]].join("[").concat("]"));
    return output.concat([nestedKey, keyValue[1]].join("="));
  }, []);
}

var convertToQueryStr = function(arrayKeyValueStr) {
  return arrayKeyValueStr.join("&");
}

console.log(convertToQueryStr(joinArrayStrings(turnMapToArray(queryMap))));