Google Map API JavaScript function has an issue

Question

I am Fetching JSON data from REST APIs, in array

 

for (var i = 0; i < results.length; i++) {

if (results[i]["Geolocation"] != null) {

 }

}

There is date field called Meeting Start date, I would like to store them in array and display as a filter, I have used below function there some issue on it

// Function helper for date humanities format 

// argument csd is MeetingStartDate as .js Date() object

function hData(csd) {

if (Object.prototype.toString.call(csd) !== '[object Date]') { return 'Not Specified'; };

var tx = new Date();

tx.setMonth(tx.getMonth() - 6);

if (tx.getTime() < csd.getTime()) { return 'In last 6 Months'; };

tx = new Date();

tx.setFullYear(tx.getFullYear() - 1);

if (tx.getTime() < csd.getTime()) { return 'In last 12 Months'; };

tx = new Date();

tx.setFullYear(tx.getFullYear() - 5);

if (tx.getTime() < csd.getTime()) { return 'In last 5 Years'; };

return 'More than 5 Years';

}

 

 

I would like to filter data by  In last 6 Months, In last 12 Months events on Google map

please see the image 

 Is there any issue or best way to do it, many thanks