Use String#startsWith instead of String#indexOf

src/ol/format/WFS.js

@@ -822,7 +822,7 @@ function getTypeName(featurePrefix, featureType) {
   featurePrefix = featurePrefix ? featurePrefix : FEATURE_PREFIX;
   const prefix = featurePrefix + ':';
   // The featureType already contains the prefix.
-  if (featureType.indexOf(prefix) === 0) {
+  if (featureType.startsWith(prefix)) {
     return featureType;
   } else {
     return prefix + featureType;

src/ol/format/WKB.js

@@ -864,7 +864,7 @@ class WKB extends FeatureFormat {
         options.dataProjection && getProjection(options.dataProjection);
       if (dataProjection) {
         const code = dataProjection.getCode();
-        if (code.indexOf('EPSG:') === 0) {
+        if (code.startsWith('EPSG:')) {
           srid = Number(code.substring(5));
         }
       }