Javascript sort alphabetically matching the beginning of string then alphabetically for contained text

I need help sorting through some data.
Say I type "piz" in a searchfield. I get in return and array with all the entries that contain "piz".

I now want to display them in the following order:

pizza 
 pizzeria
 apizzetto
 berpizzo
 

First the items that start with what I typed in alphabetical order then the ones that contain what I typed in alphabetical order.

Instead if I sort them alphabetically I get the following

apizzetto
 berpizzo
 pizza 
 pizzeria
 

Does anyone know how to do this?
Thanks for your help.

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