Checking Dynamics CRM user team membership with organization data service

With the all the recent news about Dynamics 365, this post probably seems a tad outdated, but today I had a colleague ask me for a way to check whether a user is a member of a team in a Dynamics CRM 2015 organization using JavaScript. Without further commentary, here goes:

//get the userid
var userid = Xrm.Page.context.getUserId();

//check if the user is on the team using a synchronous odata call
function isUserOnTeam(userid, teamid){
	//assume user is not on the team
	var returnvalue = false;
	var oDataSetName = "TeamMembershipSet";
	var filter = "SystemUserId eq guid' " + userid + " ' and TeamId eq guid' " + teamid + "'";
	var columns = "*";
	var requestResults = retrieveMultipleSync(oDataSetName, columns, filter);
	
	if (requestResults != null) {
		//more than zero results -> user is on the team
		if(requestResults.results.length>0){
			returnvalue = true;
		}
	}
	return returnvalue;
}

//helper function for making sync odata calls - taken from https://rajeevpentyala.com/2012/05/27/retrieve-multiple-records-synchronously-using-odata-jquery-in-crm-2011/
function retrieveMultipleSync(odataSetName, select, filter) {
	// Get Server URL
	var serverUrl = "";
	if (Xrm.Page.context.getClientUrl) {
		//Post UR 12
		serverUrl = Xrm.Page.context.getClientUrl();
	}
	else {
		//Pre UR 12
		serverUrl = Xrm.Page.context.getServerUrl();
	}
	var ODATA_ENDPOINT = "/XRMServices/2011/OrganizationData.svc";
	var odataUri = serverUrl + ODATA_ENDPOINT + "/" + odataSetName + "?";
	if (select) {
		odataUri += "$select=" + select;
	}
	if (filter) {
		odataUri += "&" + "$filter=" + filter;
	}
	var service = getRequestObject();
	if (service != null) {
		service.open("GET", odataUri, false);
		service.setRequestHeader("X-Requested-Width", "XMLHttpRequest");
		service.setRequestHeader("Accept", "application/json,text/javascript, */*");
		service.send(null);
		var requestResults = eval('(' + service.responseText + ')').d;
		return requestResults;
	}
}

//helper function for making xmlhttp requests
function getRequestObject() {
	if (window.XMLHttpRequest) {
		return new window.XMLHttpRequest;
	}
	else {
		try {
			return new ActiveXObject("MSXML2.XMLHTTP.3.0");
		}
		catch (ex) {
			return null;
		}
	}
}