On Google Maps API, load infowindow only after click - google-maps-api-3

Question

I have several hundreds of Google Maps markers whose info is fetched from a database (allDbEntries.length), each marker associated with a infowindow which opens after the user clicks on a marker. Each infoWindow has one or more image's URLs in its htmlInfoContent.
const map = new google.maps.Map(document.getElementById('map'), mapOptions)
// Add the markers and infowindows to the map
for (var i = 0; i < allDbEntries.length; i++) {
const el = allDbEntries[i]
const marker = new google.maps.Marker({
position: { lat: el.data_coord_latit, lng: el.data_coord_long },
map: map,
title: el.car_brand + ' ' + el.car_model
})
var htmlInfoContent = ''
for (var photoIndex = 1; photoIndex <= 4; photoIndex++) {
if (el['foto' + photoIndex]) {
const photoUrl = requestImageUrl + el['foto' + photoIndex]
htmlInfoContent += `<img width="200" src="${photoUrl}"><br>`
}
}
const infowindow = new google.maps.InfoWindow({
content: htmlInfoContent
})
marker.addListener('click', (e) => {
infowindow.open(map, marker)
return true
})
}
The problem is that I'm using this for a mobile APP (Android) or even for mobile browsers, and every time the map is loaded, hundreds of images are loaded automatically consuming the bandwidth of the mobile device.
How can I load the content of htmlInfoContent (particularly images) in a marker only after clicking on that marker?
As you can see from Dev Tools, every time I open the map, all the images are loaded consuming too much bandwidth

Answer 1

Found the solution. I had to put the htmlInfoContent in an array, and I had to use an anonymous self-invoking function which returned the function which deals with the click event handler. In this way the html content is only set after the marker is clicked.
const map = new google.maps.Map(document.getElementById('map'), mapOptions)
const infowindow = new google.maps.InfoWindow()
var htmlInfoContent = []
// Add the markers and infowindows to the map
for (var i = 0; i < allDbEntries.length; i++) {
const el = allDbEntries[i]
const marker = new google.maps.Marker({
position: { lat: el.data_coord_latit, lng: el.data_coord_long },
map: map,
title: el.car_brand + ' ' + el.car_model
})
var htmlInfoContent[i] = ''
for (var photoIndex = 1; photoIndex <= 4; photoIndex++) {
if (el['foto' + photoIndex]) {
const photoUrl = requestImageUrl + el['foto' + photoIndex]
htmlInfoContent[i] += `<img width="200" src="${photoUrl}"><br>`
}
}
google.maps.event.addListener(marker, 'click', (function (marker, i) {
return function () {
infowindow.setContent(htmlInfoContent[i])
infowindow.open(map, marker)
}
})(marker, i))
}