diff --git a/config/jsdoc/api/template/tmpl/members.tmpl b/config/jsdoc/api/template/tmpl/members.tmpl
index 243e1f22cd..19f224e3d5 100644
--- a/config/jsdoc/api/template/tmpl/members.tmpl
+++ b/config/jsdoc/api/template/tmpl/members.tmpl
@@ -14,7 +14,7 @@ if (data.type && data.type.names) {
         <div class="anchor" id="<?js= id ?>">
         </div>
         <h4 class="name">
-            <?js= data.attribs + (data.scope === 'static' ? longname : name.indexOf('module:') === 0 ? name.split('/').pop() : name)  + typeSignature ?>
+            <?js= data.attribs + (data.scope === 'static' ? longname : name.startsWith('module:') ? name.split('/').pop() : name)  + typeSignature ?>
             <?js= this.partial('stability.tmpl', data) ?>
         </h4>
     </div>
diff --git a/config/jsdoc/api/template/tmpl/navigation.tmpl b/config/jsdoc/api/template/tmpl/navigation.tmpl
index 982bc186f6..d4666b9805 100644
--- a/config/jsdoc/api/template/tmpl/navigation.tmpl
+++ b/config/jsdoc/api/template/tmpl/navigation.tmpl
@@ -2,7 +2,7 @@
 var self = this;
 
 function toShortName(name) {
-    return name.indexOf('module:') === 0 ? name.split('/').pop() : name;
+    return name.startsWith('module:') ? name.split('/').pop() : name;
 }
 
 function getItemCssClass(type) {
diff --git a/config/jsdoc/api/template/tmpl/params.tmpl b/config/jsdoc/api/template/tmpl/params.tmpl
index d00a53401b..c5529e932f 100644
--- a/config/jsdoc/api/template/tmpl/params.tmpl
+++ b/config/jsdoc/api/template/tmpl/params.tmpl
@@ -1,11 +1,11 @@
 <?js
     var params = obj;
-    
+
     /* sort subparams under their parent params (like opts.classname) */
     var parentParam = null;
     params.forEach(function(param, i) {
         if (!param) { return; }
-        if ( parentParam && param.name && param.name.indexOf(parentParam.name + '.') === 0 ) {
+        if (parentParam && param.name && param.name.startsWith(parentParam.name + '.')) {
             param.name = param.name.substr(parentParam.name.length+1);
             parentParam.subparams = parentParam.subparams || [];
             parentParam.subparams.push(param);
@@ -15,30 +15,30 @@
             parentParam = param;
         }
     });
-    
+
     /* determine if we need extra "attributes" column */
     params.hasAttributes = false;
     params.hasName = false;
-    
+
     var colspan = 2;
     params.forEach(function(param) {
         if (!param) { return; }
         if (param.type && param.type.names && param.type.names.includes('undefined')) {
             param.optional = true;
         }
-        if (param.name.indexOf('var_') == 0) {
+        if (param.name.startsWith('var_')) {
             params.hasAttributes = true;
             param.variable = true;
         }
-        
+
         if (param.optional || param.nullable) {
             params.hasAttributes = true;
         }
-        
+
         if (param.name) {
             params.hasName = true;
         }
-        
+
     });
 ?>
 
@@ -48,25 +48,25 @@
 		<?js if (params.hasName) {?>
 		<th>Name</th>
 		<?js } ?>
-		
+
 		<th>Type</th>
-		
+
 		<th class="last">Description</th>
 	</tr>
 	</thead>
-	
+
 	<tbody>
 	<?js
         var self = this;
 	    params.forEach(function(param) {
 	        if (!param) { return; }
 	?>
-	
+
         <tr class="<?js= (param.stability && param.stability !== 'stable') ? 'unstable' : '' ?>">
             <?js if (params.hasName) {?>
                 <td class="name"><code><?js= param.name.replace(/^opt_/, "") ?></code></td>
             <?js } ?>
-            
+
             <?js if (!param.subparams) {?>
             <td class="type">
             <?js if (param.type && param.type.names) {?>
@@ -87,7 +87,7 @@
                 <?js= self.partial('params.tmpl', param.subparams) ?>
             <?js } ?></td>
         </tr>
-	
+
 	<?js }); ?>
 	</tbody>
 </table>
\ No newline at end of file
diff --git a/config/jsdoc/api/template/tmpl/properties.tmpl b/config/jsdoc/api/template/tmpl/properties.tmpl
index 97a3d23abd..c3b4ebeab1 100644
--- a/config/jsdoc/api/template/tmpl/properties.tmpl
+++ b/config/jsdoc/api/template/tmpl/properties.tmpl
@@ -1,11 +1,11 @@
 <?js
     var props = obj;
-    
+
     /* sort subprops under their parent props (like opts.classname) */
     var parentProp = null;
     props.forEach(function(prop, i) {
         if (!prop) { return; }
-        if ( parentProp && prop.name && prop.name.indexOf(parentProp.name + '.') === 0 ) {
+        if (parentProp && prop.name && prop.name.startsWith(parentProp.name + '.')) {
             prop.name = prop.name.substr(parentProp.name.length+1);
             parentProp.subprops = parentProp.subprops || [];
             parentProp.subprops.push(prop);
@@ -15,23 +15,23 @@
             parentProp = prop;
         }
     });
-    
+
     /* determine if we need extra columns, "attributes" and "default" */
     props.hasAttributes = false;
     props.hasDefault = false;
     props.hasName = false;
-    
+
     props.forEach(function(prop) {
         if (!prop) { return; }
-        
+
         if (prop.optional || prop.nullable) {
             props.hasAttributes = true;
         }
-        
+
         if (prop.name) {
             props.hasName = true;
         }
-        
+
         if (typeof prop.defaultvalue !== 'undefined') {
             props.hasDefault = true;
         }
@@ -44,51 +44,51 @@
 		<?js if (props.hasName) {?>
 		<th>Name</th>
 		<?js } ?>
-		
+
 		<th>Type</th>
-		
+
 		<?js if (props.hasAttributes) {?>
 		<th>Argument</th>
 		<?js } ?>
-		
+
 		<?js if (props.hasDefault) {?>
 		<th>Default</th>
 		<?js } ?>
-		
+
 		<th class="last">Description</th>
 	</tr>
 	</thead>
-	
+
 	<tbody>
 	<?js
         var self = this;
 	    props.forEach(function(prop) {
 	        if (!prop) { return; }
 	?>
-	
+
         <tr>
             <?js if (props.hasName) {?>
                 <td class="name"><code><?js= prop.name ?></code></td>
             <?js } ?>
-            
+
             <td class="type">
             <?js if (prop.type && prop.type.names) {?>
                 <?js= self.partial('type.tmpl', prop.type.names) ?>
             <?js } ?>
             </td>
-            
+
             <?js if (props.hasAttributes) {?>
                 <td class="attributes">
                 <?js if (prop.optional) { ?>
                     &lt;optional><br>
                 <?js } ?>
-                    
+
                 <?js if (prop.nullable) { ?>
                     &lt;nullable><br>
                 <?js } ?>
                 </td>
             <?js } ?>
-            
+
             <?js if (props.hasDefault) {?>
                 <td class="default">
                 <?js if (typeof prop.defaultvalue !== 'undefined') { ?>
@@ -96,12 +96,12 @@
                 <?js } ?>
                 </td>
             <?js } ?>
-            
+
             <td class="description last"><?js= prop.description ?><?js if (prop.subprops) { ?>
                 <h6>Properties</h6><?js= self.partial('properties.tmpl', prop.subprops) ?>
             <?js } ?></td>
         </tr>
-	
+
 	<?js }); ?>
 	</tbody>
 </table>
\ No newline at end of file
diff --git a/config/jsdoc/api/template/tmpl/returns.tmpl b/config/jsdoc/api/template/tmpl/returns.tmpl
index b83aa5797a..41a25b788b 100644
--- a/config/jsdoc/api/template/tmpl/returns.tmpl
+++ b/config/jsdoc/api/template/tmpl/returns.tmpl
@@ -10,9 +10,9 @@ returns.forEach(function (ret, i) {
         var name = ret.name || ret.description;
         var startSpacePos = name.indexOf(" ");
 
-        if (parentReturn !== null && name.indexOf(parentReturn.name + '.') === 0) {
+        if (parentReturn !== null && name.startsWith(parentReturn.name + '.')) {
             ret.name = isNamed ? name.substr(parentReturn.name.length + 1) : name.substr(parentReturn.name.length + 1, startSpacePos - (parentReturn.name.length + 1));
-        
+
             parentReturn.subReturns = parentReturn.subReturns || [];
             parentReturn.subReturns.push(ret);
             returns[i] = null;
@@ -20,7 +20,7 @@ returns.forEach(function (ret, i) {
             if (!isNamed) {
                 ret.name = ret.description.substr(0, startSpacePos !== -1 ? startSpacePos : ret.description.length);
             }
-            
+
             parentReturn = ret;
         }
     }
@@ -54,7 +54,7 @@ if (returns.length > 1) {
                     ret.type.names.forEach(function(name, i) { ?>
                         <?js= self.linkto(name, self.htmlsafe(name)) ?>
                         <?js if (i < ret.type.names.length-1) { ?> | <?js } ?>
-                    <?js }); 
+                    <?js });
                 }
             ?>
             </td>
diff --git a/config/jsdoc/info/publish.js b/config/jsdoc/info/publish.js
index 9c469fed2e..5d1c015f1b 100644
--- a/config/jsdoc/info/publish.js
+++ b/config/jsdoc/info/publish.js
@@ -34,7 +34,7 @@ exports.publish = function (data, opts) {
         return (
           this.meta &&
           this.meta.path &&
-          this.longname.indexOf('<anonymous>') !== 0 &&
+          !this.longname.startsWith('<anonymous>') &&
           this.longname !== 'module:ol'
         );
       },
diff --git a/config/jsdoc/plugins/observable.cjs b/config/jsdoc/plugins/observable.cjs
index b4da2ae2ef..14e7f38658 100644
--- a/config/jsdoc/plugins/observable.cjs
+++ b/config/jsdoc/plugins/observable.cjs
@@ -29,10 +29,10 @@ exports.handlers = {
         observable.name = name;
         observable.readonly =
           typeof observable.readonly == 'boolean' ? observable.readonly : true;
-        if (doclet.name.indexOf('get') === 0) {
+        if (doclet.name.startsWith('get')) {
           observable.type = doclet.returns[0].type;
           observable.description = doclet.returns[0].description;
-        } else if (doclet.name.indexOf('set') === 0) {
+        } else if (doclet.name.startsWith('set')) {
           observable.readonly = false;
         }
         if (doclet.stability) {
diff --git a/examples/drag-and-drop-custom-kmz.js b/examples/drag-and-drop-custom-kmz.js
index 81ad5d95b5..e24427a73e 100644
--- a/examples/drag-and-drop-custom-kmz.js
+++ b/examples/drag-and-drop-custom-kmz.js
@@ -27,7 +27,7 @@ function getKMLImage(href) {
   let url = href;
   let path = window.location.href;
   path = path.slice(0, path.lastIndexOf('/') + 1);
-  if (href.indexOf(path) === 0) {
+  if (href.startsWith(path)) {
     const regexp = new RegExp(href.replace(path, '') + '$', 'i');
     const kmlFile = zip.file(regexp)[0];
     if (kmlFile) {
diff --git a/examples/vector-tile-selection.js b/examples/vector-tile-selection.js
index 5dd228dcae..57325b7e4d 100644
--- a/examples/vector-tile-selection.js
+++ b/examples/vector-tile-selection.js
@@ -86,7 +86,7 @@ map.on(['click', 'pointermove'], function (event) {
     }
     const fid = feature.getId();
 
-    if (selectElement.value.indexOf('singleselect') === 0) {
+    if (selectElement.value.startsWith('singleselect')) {
       selection = {};
     }
     // add selected feature to lookup
diff --git a/src/ol/color.js b/src/ol/color.js
index 482ebb01a1..e47c5cebf4 100644
--- a/src/ol/color.js
+++ b/src/ol/color.js
@@ -168,11 +168,11 @@ function fromStringInternal_(s) {
       }
     }
     color = [r, g, b, a / 255];
-  } else if (s.indexOf('rgba(') == 0) {
+  } else if (s.startsWith('rgba(')) {
     // rgba()
     color = s.slice(5, -1).split(',').map(Number);
     normalize(color);
-  } else if (s.indexOf('rgb(') == 0) {
+  } else if (s.startsWith('rgb(')) {
     // rgb()
     color = s.slice(4, -1).split(',').map(Number);
     color.push(1);
@@ -225,7 +225,5 @@ export function isStringColor(s) {
   if (NAMED_COLOR_RE_.test(s)) {
     s = fromNamed(s);
   }
-  return (
-    HEX_COLOR_RE_.test(s) || s.indexOf('rgba(') === 0 || s.indexOf('rgb(') === 0
-  );
+  return HEX_COLOR_RE_.test(s) || s.startsWith('rgba(') || s.startsWith('rgb(');
 }
diff --git a/src/ol/format/WFS.js b/src/ol/format/WFS.js
index 88570faaf6..c1b1baf133 100644
--- a/src/ol/format/WFS.js
+++ b/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;
diff --git a/src/ol/format/WKB.js b/src/ol/format/WKB.js
index e18a410fac..d757aa68c1 100644
--- a/src/ol/format/WKB.js
+++ b/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));
         }
       }
diff --git a/src/ol/source/ogcTileUtil.js b/src/ol/source/ogcTileUtil.js
index 2925218236..83e302cf06 100644
--- a/src/ol/source/ogcTileUtil.js
+++ b/src/ol/source/ogcTileUtil.js
@@ -114,7 +114,7 @@ export function getMapTileUrlTemplate(links, mediaType) {
       }
       if (knownMapMediaTypes[link.type]) {
         fallbackUrlTemplate = link.href;
-      } else if (!fallbackUrlTemplate && link.type.indexOf('image/') === 0) {
+      } else if (!fallbackUrlTemplate && link.type.startsWith('image/')) {
         fallbackUrlTemplate = link.href;
       }
     }
diff --git a/tasks/generate-info.js b/tasks/generate-info.js
index bcf89bedce..3c772ccfd0 100644
--- a/tasks/generate-info.js
+++ b/tasks/generate-info.js
@@ -5,7 +5,7 @@ import {fileURLToPath} from 'url';
 import {spawn} from 'child_process';
 import {walk} from 'walk';
 
-const isWindows = process.platform.indexOf('win') === 0;
+const isWindows = process.platform.startsWith('win');
 const baseDir = dirname(fileURLToPath(import.meta.url));
 
 const sourceDir = path.join(baseDir, '..', 'src');