refactor: extract add extension method
refactor: extract add extension method

NathanaelA/nativescript-cli,NathanaelA/nativescript-cli,NativeScript/nativescript-cli,NativeScript/nativescript-cli,NathanaelA/nativescript-cli,NativeScript/nativescript-cli,NathanaelA/nativescript-cli,NativeScript/nativescript-cli