One common action when working with features within a vector layer is its selection, and, of course, OpenLayers has some feature selection controls that are available to us. We've already seen this demonstrated in earlier recipes, such as the Removing or cloning features using overlays recipe in Chapter 3, Working with Vector Layers. This recipe showed us how to select one feature at a time with a click or tap gesture.
This recipe will show you how to select multiple features at once using a combination of interactions. The
ol.interaction.Select class is for the render intent and grouping of selected features, and the other is
ol.interaction.DragBox, which is used to enable the user to drag out a rectangle over the map. The joint effort of these two controls will produce a multiselect capability.
Once these features have been selected, we'll display the selected count and enable the user to delete the selected features from the sidebar.