leafletMap: is there any different between L.map and

I am following the leafletjs guide from here :
https://vue2-leaflet.netlify.app/components/LIcon.html#demo

and just adding stuffs into the component like this:

<l-map ref="myMapstats" :zoom="zoom" :center="center">
        <l-tile-layer
          url="https://{s}.tile.openstreetmap.de/tiles/osmde/{z}/{x}/{y}.png"
          attribution='&copy; <a target="_blank" 
           href="http://osm.org/copyright">OpenStreetMap</a>'
        ></l-tile-layer>
        <l-marker 
        :lat-lng="[47.413220, -1.209482]"
        :icon="icon" > 
        </l-marker>
          <l-icon 
           :icon-anchor="iconAnchor" 
           :icon-size="iconSize" 
            :popup- 
           : anchor="popupAnchor">
           icon-url="static/images/baseball-marker.png" >
          </l-icon>


          <l-popup>
           LOL
          </l-popup>
        </l-marker>
      </l-map>

And importing like this: import {LMap, LTileLayer, LMarker, LIcon} from ‘vue2-leaflet’;
So I am able to use LMAP and other components from ‘vue2-leaflet’;

But, I can see many people are using the same leafletmap in different way,
and the L.Marker in this way and then adding to the map, see below:

var map = L.map('map').setView([51.495, -0.09], 15);
var osmUrl = 'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png';
var osmLayer = new L.TileLayer(osmUrl, {
  maxZoom: 19,
  attribution: 'Map data © OpenStreetMap contributors'
});
map.addLayer(osmLayer);

var marker1 = L.marker([51.497, -0.09], {
  title: "marker_1"
}).addTo(map).bindPopup("Marker 1").on('click', clickZoom);

So for example I want to create a function ‘clickHandler(index)’, in my map ( the first Example ), and then calling the function from marker and in function I am using the LMap.setView()…., and when I run I am getting error, LMAP not define.

Just want to know id there any differennce between :
'<l-map> </l-map>' and 'var map = L.map('map')'

Thanks in advance!

 <l-marker
          v-for="(marker, index) in markers"
          :key="index"
          @click="clickHandler(index)"
  >

....... more code here ....

methods: {
   clickHandler(index) {
      LMap.setView(markers[index].location, 13);
      //this.$refs.myMapstats;
      markers[index].openPopUp();
    },
}