[Vuejs]-.scroll() works on codepen but doesn't in my Electron Vue app

Electron 1.8.2 is based on Chrome 59.0.3071.115, which has partial support of the relatively new “Scroll Behavior” specification (which includes the Element.scroll() method you are using).

Meanwhile you can use the smooth scroll polyfill:

npm install smoothscroll-polyfill

And in App.vue:

require('smoothscroll-polyfill').polyfill();