Distance between coordinates

 
var json =  [
  {
    "id" : '1',
    "name" : "Marker 1",
    "lat" : '-25.55913',
    "lng" : '-49.282099'
  },
  {
    "id" : '2',
    "name" : "Marker 2",
    "lat" : '-25.56930',
    "lng" : '-49.292200'
  },
  {
    "id" : '3',
    "name" : "Marker 3",
    "lat" : '-25.53930',
    "lng" : '-49.292200'
  }
];

var arr = [];

json.map(function(value){
if(getDistanceBetweenPoints({"lat":value.lat,"lng":value.lng},{"lat":
-25.5591156,"lng":
-49.28208870000003},'km') < 
5.180150806097898){
  arr.push(value);
}

});

console.log(arr);


function toRad(x) {
    return x * Math.PI / 180;
  }

function getDistanceBetweenPoints(pos1, pos2, units) {

    var earthRadius = {
      miles: 3958.8,
      km: 6371
    };

    var R = earthRadius[units || 'miles'];
    var lat1 = pos1.lat;
    var lon1 = pos1.lng;
    var lat2 = pos2.lat;
    var lon2 = pos2.lng;

    var dLat = toRad((lat2 - lat1));
    var dLon = toRad((lon2 - lon1));
    var a = Math.sin(dLat / 2) * Math.sin(dLat / 2) +
      Math.cos(toRad(lat1)) * Math.cos(toRad(lat2)) *
      Math.sin(dLon / 2) *
      Math.sin(dLon / 2);
    var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
    var d = R * c;

    return d;

  }