diff --git a/src/app/date-navigator/date-navigator.component.ts b/src/app/date-navigator/date-navigator.component.ts
index 60baf26..b5fbf94 100644
--- a/src/app/date-navigator/date-navigator.component.ts
+++ b/src/app/date-navigator/date-navigator.component.ts
@@ -1,4 +1,4 @@
-import {Component, EventEmitter, Input, OnInit, Output, QueryList, ViewChild, ViewChildren} from '@angular/core';
+import {Component, EventEmitter, Input, Output, QueryList, ViewChildren} from '@angular/core';
 import * as moment from 'moment';
 import {Moment} from 'moment';
 import {DatePickerDirective, IDatePickerDirectiveConfig} from 'ng2-date-picker';
diff --git a/src/app/energie-verbruik/energie-verbruik.component.ts b/src/app/energie-verbruik/energie-verbruik.component.ts
index b3279a0..14152c9 100644
--- a/src/app/energie-verbruik/energie-verbruik.component.ts
+++ b/src/app/energie-verbruik/energie-verbruik.component.ts
@@ -50,8 +50,8 @@ export class EnergieVerbruikComponent implements OnInit {
 
   public ngOnInit() {
       combineLatest([ this.activatedRoute.paramMap, this.activatedRoute.queryParamMap ]).subscribe(combined => {
-        const params: ParamMap = <ParamMap>combined[0];
-        const queryParams: ParamMap = <ParamMap>combined[1];
+        const params: ParamMap = combined[0];
+        const queryParams: ParamMap = combined[1];
 
         const verbruiksoortParam = params.get('verbruiksoort');
         const periodeParam = params.get('periode');
diff --git a/src/app/error-handling/error-handing.service.ts b/src/app/error-handling/error-handing.service.ts
index e9fda26..9db3f3c 100644
--- a/src/app/error-handling/error-handing.service.ts
+++ b/src/app/error-handling/error-handing.service.ts
@@ -13,7 +13,7 @@ export class ErrorHandingService {
     return this.errorSubject.asObservable();
   }
 
-  public handleError(message: String, causedBy: any) {
+  public handleError(message: string, causedBy: any) {
     console.error(message, causedBy);
     this.spinnerService.hide();
     this.errorSubject.next(new Error(message, causedBy));
diff --git a/src/app/error-handling/error-handling.component.ts b/src/app/error-handling/error-handling.component.ts
index 596f1a8..71ebc2f 100644
--- a/src/app/error-handling/error-handling.component.ts
+++ b/src/app/error-handling/error-handling.component.ts
@@ -12,7 +12,7 @@ export class ErrorHandlingComponent implements OnInit {
   @ViewChild('errorDialogTemplate', { static: true })
   private readonly errorDialogTemplate: TemplateRef<any>;
 
-  public message: String;
+  public message: string;
   private modal: NgbModalRef;
 
   constructor(private readonly modalService: NgbModal,
@@ -25,7 +25,7 @@ export class ErrorHandlingComponent implements OnInit {
   }
 
   public handleError(error: Error): void {
-    this.message = error.message;
+    this.message = error.message.valueOf();
     this.openDialog();
   }
 
diff --git a/src/app/error-handling/error.ts b/src/app/error-handling/error.ts
index 0204252..bf724ec 100644
--- a/src/app/error-handling/error.ts
+++ b/src/app/error-handling/error.ts
@@ -1,5 +1,5 @@
 export class Error {
 
-  constructor(public message: String, public causedBy: any) {
+  constructor(public message: string, public causedBy: any) {
   }
 }