Vuejs Warning expected boolean found string

Instead of

<vue-flip active-hover="TRUE" class="flip">

you should use

<vue-flip v-bind:active-hover="true" class="flip">

or shorter

<vue-flip :active-hover="true" class="flip">

The default when providing a prop with no value is true

Change this

<vue-flip active-hover="TRUE" class="flip">

<vue-flip active-hover class="flip">

Related