diff --git a/src/app/classes/interceptor.ts b/src/app/classes/interceptor.ts
index 9877231c1..587c9ca9d 100644
--- a/src/app/classes/interceptor.ts
+++ b/src/app/classes/interceptor.ts
@@ -32,7 +32,7 @@ export class CoreInterceptor implements HttpInterceptor {
      */
     static serialize(obj: any, addNull?: boolean): string {
         let query = '';
-        let fullSubName;
+        let fullSubName: string;
         let subValue;
         let innerObj;
 
@@ -68,10 +68,11 @@ export class CoreInterceptor implements HttpInterceptor {
         const newReq = req.clone({
             headers: req.headers.set('Content-Type', 'application/x-www-form-urlencoded'),
             body: typeof req.body == 'object' && String(req.body) != '[object File]' ?
-                CoreInterceptor.serialize(req.body) : req.body
+                CoreInterceptor.serialize(req.body) : req.body,
         });
 
         // Pass on the cloned request instead of the original request.
         return next.handle(newReq);
     }
+
 }
diff --git a/src/app/classes/native-to-angular-http.ts b/src/app/classes/native-to-angular-http.ts
index e21e7eb7e..08349dd30 100644
--- a/src/app/classes/native-to-angular-http.ts
+++ b/src/app/classes/native-to-angular-http.ts
@@ -92,7 +92,8 @@ export class CoreNativeToAngularHttpResponse<T> extends AngularHttpResponse<T> {
             headers: new HttpHeaders(nativeResponse.headers),
             status: nativeResponse.status,
             statusText: HTTP_STATUS_MESSAGES[nativeResponse.status] || '',
-            url: nativeResponse.url || ''
+            url: nativeResponse.url || '',
         });
     }
+
 }
diff --git a/src/app/classes/queue-runner.ts b/src/app/classes/queue-runner.ts
index fbc5d1d22..aa9868ccd 100644
--- a/src/app/classes/queue-runner.ts
+++ b/src/app/classes/queue-runner.ts
@@ -53,6 +53,7 @@ export type CoreQueueRunnerAddOptions = {
  * A queue to prevent having too many concurrent executions.
  */
 export class CoreQueueRunner {
+
     protected queue: {[id: string]: CoreQueueRunnerItem} = {};
     protected orderedQueue: CoreQueueRunnerItem[] = [];
     protected numberRunning = 0;
@@ -140,4 +141,5 @@ export class CoreQueueRunner {
 
         return item.deferred.promise;
     }
+
 }
diff --git a/src/app/classes/singletons-factory.ts b/src/app/classes/singletons-factory.ts
index 3415762a2..562b9a3a4 100644
--- a/src/app/classes/singletons-factory.ts
+++ b/src/app/classes/singletons-factory.ts
@@ -80,4 +80,5 @@ export class CoreSingletonsFactory {
 
         };
     }
+
 }
diff --git a/src/app/singletons/logger.ts b/src/app/singletons/logger.ts
index c189192da..ee8f9fc4e 100644
--- a/src/app/singletons/logger.ts
+++ b/src/app/singletons/logger.ts
@@ -27,12 +27,18 @@ import { environment } from '@/environments/environment';
  * Then you can call the log function you want to use in this logger instance.
  */
 export class CoreLogger {
+
     log: LogFunction;
     info: LogFunction;
     warn: LogFunction;
     debug: LogFunction;
     error: LogFunction;
 
+    // Avoid creating singleton instances.
+    private constructor() {
+        // Nothing to do.
+    }
+
     /**
      * Get a logger instance for a certain class, service or component.
      *
@@ -88,6 +94,7 @@ export class CoreLogger {
             logFn.apply(null, args);
         };
     }
+
 }
 
 /**
diff --git a/src/app/singletons/url.ts b/src/app/singletons/url.ts
index 36a2d9acb..d17af5bc6 100644
--- a/src/app/singletons/url.ts
+++ b/src/app/singletons/url.ts
@@ -72,7 +72,9 @@ interface UrlParts {
 export class CoreUrl {
 
     // Avoid creating singleton instances.
-    private constructor() {}
+    private constructor() {
+        // Nothing to do.
+    }
 
     /**
      * Parse parts of a url, using an implicit protocol if it is missing from the url.
@@ -123,14 +125,14 @@ export class CoreUrl {
 
         // Match using common suffixes.
         const knownSuffixes = [
-            '\/my\/?',
-            '\/\\\?redirect=0',
-            '\/index\\\.php',
-            '\/course\/view\\\.php',
-            '\/login\/index\\\.php',
-            '\/mod\/page\/view\\\.php',
+            '/my/?',
+            '/\\?redirect=0',
+            '/index\\.php',
+            '/course/view\\.php',
+            '\\/login/index\\.php',
+            '/mod/page/view\\.php',
         ];
-        const match = url.match(new RegExp(`^https?:\/\/(.*?)(${knownSuffixes.join('|')})`));
+        const match = url.match(new RegExp(`^https?://(.*?)(${knownSuffixes.join('|')})`));
 
         if (match) {
             return match[1];
@@ -184,10 +186,10 @@ export class CoreUrl {
      */
     static sameDomainAndPath(urlA: string, urlB: string): boolean {
         // Add protocol if missing, the parse function requires it.
-        if (!urlA.match(/^[^\/:\.\?]*:\/\//)) {
+        if (!urlA.match(/^[^/:.?]*:\/\//)) {
             urlA = `https://${urlA}`;
         }
-        if (!urlB.match(/^[^\/:\.\?]*:\/\//)) {
+        if (!urlB.match(/^[^/:.?]*:\/\//)) {
             urlB = `https://${urlB}`;
         }
 
@@ -197,4 +199,5 @@ export class CoreUrl {
         return partsA.domain == partsB.domain &&
                 CoreTextUtils.instance.removeEndingSlash(partsA.path) == CoreTextUtils.instance.removeEndingSlash(partsB.path);
     }
+
 }
diff --git a/src/app/singletons/window.ts b/src/app/singletons/window.ts
index 4ea9f6d46..2fe01da42 100644
--- a/src/app/singletons/window.ts
+++ b/src/app/singletons/window.ts
@@ -32,6 +32,11 @@ export type CoreWindowOpenOptions = {
  */
 export class CoreWindow {
 
+    // Avoid creating singleton instances.
+    private constructor() {
+        // Nothing to do.
+    }
+    
     /**
      * "Safe" implementation of window.open. It will open the URL without overriding the app.
      *
@@ -73,4 +78,5 @@ export class CoreWindow {
             }
         }
     }
+
 }