How to move from npm to yarn in my laravel, vue/cli apps?

I want to move from npm to yarn in my laravel, vue/cli apps and viewing / reading some tutorials I see yarn.lock file mentioned ion the root of the app. But running command for new laravel app creation: laravel new ya_prj I do not any yarn.lock or yarn.* files in newly created project I have yarn installed :

$ yarn --version                  
0.32

Did I miss some options?

Also how can I to replace npw with yarn for my laravel 5.7-6, vue/cli 4 apps locally and on live server?

Thanks!

via Chebli Mohamed