Library components can be used for designing your "SliderDrawer" and "ListViewItem"s.
When you have a set of components that you want to use across your pages, just create a library component, and reuse it.
From the Project Explorer, open the Library pane.
Drag a FlexLayout from the toolbox to the Library. This layout represents your first library component.
Double click on the FlexLayout that you just moved. This will enable you to insert other components inside your layout.
Drag a Button inside your layout, then save your changes.
There you have it! You can use this library component across all of your pages.
Now drag "flexlayout1" (which is your library component), from the library pane to your page.
Don't forget that a library component update will be reflected to all pages using this component. This is the primary advantage of using a library.
As an example, change the background color of your button of "flexlayout1"