[Vuejs]-How can I define props?

Once you go down the object definition route, you have to do that with all the props. You can’t mix them.

You can find more information about the props here: https://v2.vuejs.org/v2/guide/components.html#Prop-Validation

Note:

Instead of defining the props as an array of strings, you can use an
object with validation requirements

I’ve highlighted the part in the manual that explains. This indicates you can do one or the other.