On his blog Christoph Rumpel explains how you can add a vue component to a Spark app.

Taylor Otwell, the creator of Laravel, is a big Vue fan and this is why you will find it in a lot of Laravel products. Spark is using Vue too. ... When I started to use Spark I wanted to use some of my already given .vue components too, but since Spark is a little bit different from standard Laravel projects I didn’t managed to use them. After some weeks of reaching out for help, I finally got the solution.