How to glue position markers when moving away on the map?

Question

JavaScript

Whether it's in mapbox or google maps.
Here is an example, I don’t understand how the mechanism works when moving away and approaching a
poke
or
a poke
Namely, when it’s close, we show the icon and how many places have the same postcode. The farther, the higher the number, because the icons are grouped together and the number grows, how do they do that?

Answer 1

For Google Maps this is done through Marker Clustering .