In the latest Vue release v2.5.11 a validation for misspelled props was created.

Copied from https://github.com/vuejs/vue/releases :

"warn misspelled keys on prop validation object (#7198) d02bb37, closes #7198"

and the vueify is generating a property validation called twoWay on my props, causing a lot of warnings on console:

[Vue warn]: Invalid key "twoWay" in validation rules object for prop "xxxxxx".

In the output of the vueify there is the following code:

var props = { center: { required: true, twoWay: true, type: Object } }