/**
    If we have a domain from settings (the directive), fill in
    any null values with ones from our measured extents
    otherwise, return the measured extent
    @param {number[]} domain A two-value array of numbers
    @param {number[]} directive A two-value array of numbers that will have any nulls filled in from the `domain` array
    @returns {number[]} The filled in domain
*/
export default function partialDomain(domain: number[] | undefined, directive: number[]): number[];