var point1 = {
  "type": "Feature",
  "properties": {},
  "geometry": {
    "type": "Point",
    "coordinates": [-75.343, 39.984]
  }
};
var point2 = {
  "type": "Feature",
  "properties": {},
  "geometry": {
    "type": "Point",
    "coordinates": [-75.534, 39.123]
  }
};
var units = "miles";
 
var points = {
  "type": "FeatureCollection",
  "features": [point1, point2]
};
 
//=points
 
var distance = turf.vincenty-inverse(point1, point2, units);
 
//=distance