NPM run - is not rendering a JS file properly

Hello GUYS , I have been all day trying with many ways to solve a problem . I have a project that I created inside XAMP Host ( in my machine , windows ) , then I started working with docker ( Laradock ) and I created the same project inside the laradock host .

Well , it is working , but when I created the Javascript with -

npm install
npm run dev

It seens that some classes in javascript was not rendered properly , javascript classes like this ones -

https://laracasts.com/series/learn-vue-2-step-by-step/episodes/20

It is not working properly , I am using -

npm vesion - 6.7.0
node version - 11.12.0


the old project was with laravel 5.6 and this one with laravel 5.8

maybe , it is rendering in a strict mode , does have any configuration that I set strict or not strict ?

Thanks a lot