Nicely written intro tutorial to Vue components with a good example.

I have a few remarks:

- the formula in the concept is not displayed correctly in 2 lines - maybe there's a better formatting in Medium.

- in your final code you display minutess instead of minutes, one `s` needs to be removed.

I am also wondering why you are separating `props` and `data` definitions from the component itself, instead of defining them inline? It's not wrong, and I think it looks clean, but I am curious what are the reasons as I haven't seen this syntax before. (BTW, I suppose many such conventions will have to change as soon as we will all start using Vue 3:)