Highlight text in vector-layer example

examples/vector-layer.js

@@ -60,20 +60,35 @@ var map = new ol.Map({
   })
 });
 
-var highlightStyleArray = [new ol.style.Style({
+var highlightStyleCache = {};
+
+var featuresOverlay = new ol.render.FeaturesOverlay({
+  map: map,
+  styleFunction: function(feature, resolution) {
+    var text = resolution < 5000 ? feature.get('name') : '';
+    if (!highlightStyleCache[text]) {
+      highlightStyleCache[text] = [new ol.style.Style({
         stroke: new ol.style.Stroke({
           color: '#f00',
           width: 1
         }),
         fill: new ol.style.Fill({
           color: 'rgba(255,0,0,0.1)'
+        }),
+        text: new ol.style.Text({
+          font: '12px Calibri,sans-serif',
+          text: text,
+          fill: new ol.style.Fill({
+            color: '#000'
+          }),
+          stroke: new ol.style.Stroke({
+            color: '#f00',
+            width: 3
+          })
         })
       })];
-
-var featuresOverlay = new ol.render.FeaturesOverlay({
-  map: map,
-  styleFunction: function(feature, resolution) {
-    return highlightStyleArray;
+    }
+    return highlightStyleCache[text];
   }
 });