code: function getMaxFromProps(props, axis) {
    if (isPlainObject(props.maxDomain) && props.maxDomain[axis] !== undefined) {
      return props.maxDomain[axis];
    }
    return typeof props.maxDomain === "number" ? props.maxDomain : undefined;
  }
docs: Returns the maxDomain from props if it exists
  @param {Object} props: the props object
  @param {String} axis: the current axis
  @returns {Number|undefined} the maxDomain based on props