Query Parameter Not Showing the Correct Parameters

Question

When I add items to the query parameters, it shows an object in the URL. How can I get it to show the items?

This is the HTML:

<form [formGroup]="submitForm" (ngSubmit)="checkOut(items)">
<input type="submit" value="Check Out">
</form>

This is the component:

public checkOut(items: any) {
this.router.navigate(['check-out'], { queryParams: { items: this.items } });
}

This is what the URL looks like:

http://localhost:4200/check-out?items=%5Bobject%20Object%5D&items=%5Bobject%20Object%5D