function getCategories(props, axis) {
  return props.categories && !Array.isArray(props.categories)
    ? props.categories[axis]
    : props.categories;
}
function getCategories(props, axis) {
  return props.categories && !Array.isArray(props.categories)
    ? props.categories[axis]
    : props.categories;
}
function getCategories ( props , axis ) { return props . categories && ! Array . isArray ( props . categories ) ? props . categories [ axis ] : props . categories ; }
Returns an array of categories for a given axis
@param {Object} props: the props object
@param {String} axis: the current axis
@returns {Array} an array of categories
Returns an array of categories for a given axis