openlayersSelection.js

  _xyz.mapview.highlight = {
    feature: null,
    layer: null,
  };

  function pointermove(e){

    // Get features from layers which have a highlight style.
    const featureArray = _xyz.map.getFeaturesAtPixel(e.pixel,{
      // Filter for layers which have a highlight style.
      layerFilter: featureLayer => {
        return Object.values(_xyz.layers.list).some(layer => {
          return layer.style && layer.style.highlight && layer.L === featureLayer;
        });
      },
      hitTolerance: 0,
    });

    // Return if no features are found.
    if (!featureArray) return;
    
    // The first feature in the array will be the feature with the highest zIndex.
    const topFeature = featureArray[0];

    // Return is feature is already highlighted.
    if (_xyz.mapview.highlight.feature === topFeature) return;

    // Redraw layer with previous highlighted feature.
    if (_xyz.mapview.highlight.layer) {

      _xyz.mapview.highlight.layer.highlight = true;
                
      _xyz.mapview.highlight.layer.L.setStyle(_xyz.mapview.highlight.layer.L.getStyle());
    }
 
    // Iterate through all features (with layer) at pixel
    _xyz.map.forEachFeatureAtPixel(e.pixel, (feature, featureLayer) => {

      if (feature === topFeature) {

        // Iterate through layers list.
        Object.values(_xyz.layers.list).some(layer => {

          // Return false to continue the arrays some method if the featureLayer does not match the current layers Openlayers object layer.L
          if (layer.L !== featureLayer) return false;

          // Assign feature id to the layer object.
          layer.highlight = feature.get('id');

          // Store layer and feature reference on the mapview object.
          _xyz.mapview.highlight.feature = feature;
          _xyz.mapview.highlight.layer = layer;

          // Redraw layer to style highlight.
          return layer.L.setStyle(layer.L.getStyle());

        });

      }
        
    },{
      layerFilter: featureLayer => {
        // Filter for layers which have a highlight style.
        return Object.values(_xyz.layers.list).some(layer => {
          return layer.style && layer.style.highlight && layer.L === featureLayer;
        });
      },
      hitTolerance: 0,
    });
 
  };

  _xyz.map.on('pointermove', pointermove);