packages/victory-core/src/victory-util/domain.js
function getDomainFromCategories(props, axis, categories) {
  categories = categories || Data.getCategories(props, axis);
  const { polar, startAngle = 0, endAngle = 360 } = props;
  if (!categories) {
    return undefined;
  }
  const minDomain = getMinFromProps(props, axis);
  const maxDomain = getMaxFromProps(props, axis);
  const stringArray = Collection.containsStrings(categories)
    ? Data.getStringsFromCategories(props, axis)
    : [];
  const stringMap =
    stringArray.length === 0
      ? null
      : stringArray.reduce((memo, string, index) => {
          memo[string] = index + 1;
          return memo;
        }, {});
  const categoryValues = stringMap ? categories.map((value) => stringMap[value]) : categories;
  const min = minDomain !== undefined ? minDomain : Collection.getMinValue(categoryValues);
  const max = maxDomain !== undefined ? maxDomain : Collection.getMaxValue(categoryValues);
  const categoryDomain = getDomainFromMinMax(min, max);
  return polar && axis === "x" && Math.abs(startAngle - endAngle) === 360
    ? getSymmetricDomain(categoryDomain, categoryValues)
    : categoryDomain;
}
function getDomainFromCategories(props, axis, categories) {
  categories = categories || Data.getCategories(props, axis);
  const { polar, startAngle = 0, endAngle = 360 } = props;
  if (!categories) {
    return undefined;
  }
  const minDomain = getMinFromProps(props, axis);
  const maxDomain = getMaxFromProps(props, axis);
  const stringArray = Collection.containsStrings(categories)
    ? Data.getStringsFromCategories(props, axis)
    : [];
  const stringMap =
    stringArray.length === 0
      ? null
      : stringArray.reduce((memo, string, index) => {
          memo[string] = index + 1;
          return memo;
        }, {});
  const categoryValues = stringMap ? categories.map((value) => stringMap[value]) : categories;
  const min = minDomain !== undefined ? minDomain : Collection.getMinValue(categoryValues);
  const max = maxDomain !== undefined ? maxDomain : Collection.getMaxValue(categoryValues);
  const categoryDomain = getDomainFromMinMax(min, max);
  return polar && axis === "x" && Math.abs(startAngle - endAngle) === 360
    ? getSymmetricDomain(categoryDomain, categoryValues)
    : categoryDomain;
}
Returns a domain based on categories if they exist
@param {Object} props: the props object
@param {String} axis: the current axis
@param {Array} categories: an array of categories corresponding to a given axis
@returns {Array|undefined} returns a domain from categories or undefined