Map is gray or white when I leave my page

Map is gray or white when I leave my page.
My problem is this: My map loads well but if I go to the menu or see other options when I return to the map, no load remains gray or white.
I solve it with the getCurrentPosition () what happens is that I occupy my location updated since it is an uber type service … so I do it with the watchPosition () and that’s where the map does not load me
Investigating I saw that the solution is to make a detector to the mosaic loading event but I have no idea what it is or how it is done if somebody guides me I thank you

  }else {

watchCurrentPosition() {
    (position)=> {
      let pos = {
        lat: position.coords.latitude,
        lng: position.coords.longitude
        let options = {
          center: new google.maps.LatLng(position.coords.latitude, position.coords.longitude),
          zoom: 16,
          mapTypeId: google.maps.MapTypeId.ROADMAP
        } = new google.maps.Map(document.getElementById("map"), options);

        let marker = new google.maps.Marker({
          icon: new google.maps.MarkerImage('//',
            new google.maps.Size(22, 22),
            new google.maps.Point(0, 18),
            new google.maps.Point(11, 11)),
          position: pos
        let nombre = this.userProv.nombre
        let content = nombre;
        this.addInfoWindow(marker, content);
    (error) => {