[leaflet] Zoom to fit all markers in Mapbox or Leaflet

How do I set view to see all markers on map in Mapbox or Leaflet? Like Google Maps API does with bounds?

E.g:

var latlngbounds = new google.maps.LatLngBounds();
for (var i = 0; i < latlng.length; i++) {
  latlngbounds.extend(latlng[i]);
}
map.fitBounds(latlngbounds);

The best way is to use the next code

var group = new L.featureGroup([marker1, marker2, marker3]);

map.fitBounds(group.getBounds());

You have an array of L.Marker:

let markers = [marker1, marker2, marker3]

let latlngs = markers.map(marker => marker.getLatLng())

let latlngBounds = L.latLngBounds(latlngs)

map.fitBounds(latlngBounds)
// OR with a smooth animation
// map.flyToBounds(latlngBounds)

You also can locate all features inside a FeatureGroup or all the featureGroups, see how it works!

//Group1_x000D_
m1=L.marker([7.11, -70.11]);_x000D_
m2=L.marker([7.33, -70.33]);_x000D_
m3=L.marker([7.55, -70.55]);_x000D_
fg1=L.featureGroup([m1,m2,m3]);_x000D_
_x000D_
//Group2_x000D_
m4=L.marker([3.11, -75.11]);_x000D_
m5=L.marker([3.33, -75.33]);_x000D_
m6=L.marker([3.55, -75.55]);_x000D_
fg2=L.featureGroup([m4,m5,m6]);_x000D_
_x000D_
//BaseMap_x000D_
baseLayer = L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png');_x000D_
var map = L.map('map', {_x000D_
  center: [3, -70],_x000D_
  zoom: 4,_x000D_
  layers: [baseLayer, fg1, fg2]_x000D_
});_x000D_
_x000D_
//locate group 1_x000D_
function LocateOne() {_x000D_
    LocateAllFeatures(map, fg1);_x000D_
}_x000D_
_x000D_
function LocateAll() {_x000D_
    LocateAllFeatures(map, [fg1,fg2]);_x000D_
}_x000D_
_x000D_
//Locate the features_x000D_
function LocateAllFeatures(iobMap, iobFeatureGroup) {_x000D_
  if(Array.isArray(iobFeatureGroup)){   _x000D_
   var obBounds = L.latLngBounds();_x000D_
   for (var i = 0; i < iobFeatureGroup.length; i++) {_x000D_
    obBounds.extend(iobFeatureGroup[i].getBounds());_x000D_
   }_x000D_
   iobMap.fitBounds(obBounds);   _x000D_
  } else {_x000D_
   iobMap.fitBounds(iobFeatureGroup.getBounds());_x000D_
  }_x000D_
}

.mymap{_x000D_
  height: 300px;_x000D_
  width: 100%;_x000D_
}

<script src="https://unpkg.com/[email protected]/dist/leaflet.js"></script>_x000D_
<link href="https://unpkg.com/[email protected]/dist/leaflet.css" rel="stylesheet"/>_x000D_
_x000D_
<div id="map" class="mymap"></div>_x000D_
<button onclick="LocateOne()">locate group 1</button>_x000D_
<button onclick="LocateAll()">locate All</button>

The 'Answer' didn't work for me some reasons. So here is what I ended up doing:

////var group = new L.featureGroup(markerArray);//getting 'getBounds() not a function error.
////map.fitBounds(group.getBounds());
var bounds = L.latLngBounds(markerArray);
map.fitBounds(bounds);//works!

For Leaflet, I'm using

    map.setView(markersLayer.getBounds().getCenter());

To fit to the visible markers only, I've this method.

fitMapBounds() {
    // Get all visible Markers
    const visibleMarkers = [];
    this.map.eachLayer(function (layer) {
        if (layer instanceof L.Marker) {
            visibleMarkers.push(layer);
        }
    });

    // Ensure there's at least one visible Marker
    if (visibleMarkers.length > 0) {

        // Create bounds from first Marker then extend it with the rest
        const markersBounds = L.latLngBounds([visibleMarkers[0].getLatLng()]);
        visibleMarkers.forEach((marker) => {
            markersBounds.extend(marker.getLatLng());
        });

        // Fit the map with the visible markers bounds
        this.map.flyToBounds(markersBounds, {
            padding: L.point(36, 36), animate: true,
        });
    }
}

var markerArray = [];
markerArray.push(L.marker([51.505, -0.09]));
...
var group = L.featureGroup(markerArray).addTo(map);
map.fitBounds(group.getBounds());

Leaflet also has LatLngBounds that even has an extend function, just like google maps.

http://leafletjs.com/reference.html#latlngbounds

So you could simply use:

var latlngbounds = new L.latLngBounds();

The rest is exactly the same.