Initializing map and marker

mapview.js

const defaultMarker = [23.7104, 90.40744]
let map = L.map('map')
map.setView(defaultMarker, 13)
//Set up the OSM layer
L.tileLayer(
    'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
        maxZoom: 18
    }).addTo(map)
L.marker(defaultMarker).addTo(map)
Bkoi.onSelect(function() {
    // get selected data from dropdown list
    let selectedPlace = Bkoi.getSelectedData()

    // center of the map
    let center = [selectedPlace.latitude, selectedPlace.longitude]
    // Update the map
    map.setView(center, 18)
    L.marker(center).addTo(map).bindPopup(selectedPlace.Address)
})