/**
 * Numeric extent — used by series + candlestick build pipelines for
 * value / category axis domains.
 */
export interface Domain {
    min: number;
    max: number;
}
/**
 * Union `next` (a freshly-computed extent) with `prev` (the prior
 * accumulator) IN PLACE on `next`, then return a fresh copy to store
 * back as the new accumulator. Idempotent when `prev` is null — `next`
 * is left untouched.
 *
 * Used by the `domain_mode: "expand"` mirror-back step in the series /
 * candlestick / cartesian build pipelines: mutating `next` in place
 * means every downstream assignment that reads from the pipeline
 * result struct automatically picks up the grown extent.
 */
export declare function expandDomainInPlace(prev: Domain | null, next: Domain): Domain;