getMarker

getMarker is a method name used in several mapping and data-visualization libraries to retrieve a marker object from a collection, layer, or registry by its identifier. The exact behavior and location of the method depend on the library in use; some APIs expose getMarker as a method on a layer object, others as a utility function that queries a marker store. In practice, the function serves as a way to obtain a reference to a previously created marker for further manipulation.

Typical signatures include getMarker(id) or getMarker(key) where id is a string or number that uniquely identifies a marker. The method returns the Marker instance if found or null/undefined if no matching marker exists. In some implementations, a variant may accept a search predicate or return an array of matches for non-unique keys. The return type is usually the concrete marker object, not a simple data descriptor.

Returned Marker objects are usually the same instances created earlier, allowing further operations such as updating position (setLatLng), changing appearance (setIcon, setOpacity), or attaching and updating popups and event handlers. This makes getMarker useful for dynamic updates in response to data changes or user interactions.

Usage scenarios include updating markers in response to data changes, implementing search or filter features, and performing batch updates. Because many libraries store markers in internal registries, getMarker may rely on an internal map from id to marker; large collections may require performance considerations. Some libraries do not provide getMarker at all, offering iteration or direct access to marker collections instead. See also: Marker, LayerGroup, MarkerLayer, Icon, Map.