How to use the proj4.toPoint function in proj4

['EPSG:4326', epsg['4326']],
  ['EPSG:4269', epsg['4269']]
])
proj4.defs('urn:x-ogc:def:crs:EPSG:4326', proj4.defs('EPSG:4326'))

///////////////////////////////////
// Utils
///////////////////////////////////
// WGS84
proj4.WGS84

// Proj
proj4.Proj('WGS84')

// toPoint
proj4.toPoint([1, 2])
proj4.toPoint([1, 2, 3])
proj4.toPoint([1, 2, 3, 4])

// Point
// WARNING: Deprecated in v3
proj4.Point([1, 2, 3, 4])

export function wgs84ToMercator(point) {
  var sourceCRS = proj4.Proj('EPSG:4326');
  var destCRS = proj4.Proj('EPSG:3857');
  var pt = new proj4.toPoint([point[1], point[0]]);
  proj4.transform(sourceCRS, destCRS, pt);
  return pt;
}
export function calcBboxFromXY(point, zoomLevel) {