I\'m using TypeScript style with single quotes, double quotes are used exclusively in HTML templates.
WebStorm/PhpStorm auto import adds import statemen
import
This behaviour is controlled by the following option:
Settings/Preferences
Editor | Code Style | TypeScript
"Punctuation" tab | Generated code -> Quote marks
As of 2017.1 version it's on new Punctuation tab and options are named a bit differently:
Punctuation