Highlight effects for L.marker.
npm install leaflet.marker.highlight --save
Highlight effects will occur in the situation that you put your mouse over the marker.
You can set it when initializing a marker.
var marker1 = L.marker([51.5, -0.09], {highlight: 'temporary'}).addTo(map);
Or you can use a method to enable the highlight effects.
marker1.enableTemporaryHighlight();
marker1.disableTemporaryHighlight();
Highlight effects are always on.
var marker1 = L.marker([51.5, -0.09], {highlight: 'permanent'}).addTo(map);
or
marker1.enablePermanentHighlight();
Cancel the marker highlight effects by
marker1.disablePermanentHighlight();