How to fill marker by result of latitude and longitude from json result?

How to fill marker by result of latitude and longitude from json result? using angular 7 ?

this.partDetailsService.getLocationData(locationArr).subscribe(res => {      
                console.log(res);    
        res.forEach((item, index) => {    
            var dataLocation = res[index]['_source']['GPS1'];      
            console.log(dataLocation);       
            var locationsLatLng = dataLocation.split(',');
           console.log(locationsLatLng);


         });

I have foreach loop get GPS1 latitude and longitude from service return latitude and longitude based on array of locationsId then store it separated by comma , on variable locationsLatLng (lat,lng) as following :

52,70
30,40
20,60
50,100

How to file marker by latitude and longitude by values exist on locationsLatLng

markers: marker = [
{
lat: ?,
lng: ?
}