The vue component throws a warning when rotation is 0 or size is md, making it difficult to determine those values programmatically.  Having those as defaults is reasonable, but the component should also accept those values explicitly.
<FontAwesomeIcon /> shouldn't consider 0 (for rotation) or 'md' (for size) as invalid prop values.
For example:
<FontAwesomeIcon
   :icon="ICON"
   :rotation="ROTATION"
   :size="SIZE"
/>