Check if the given category has the expected properties

@param  {Object} category A single category from the remote site API
@return {Boolean}         True if the category is valid.
function isValidProductCategory( category ) {
	return (
		category &&
		category.id &&
		'number' === typeof category.id &&
		category.name &&
		'string' === typeof category.name &&
		category.slug &&
		'string' === typeof category.slug
	);
}