import type { ColumnDataMap } from "./view-reader";
export interface SplitGroup {
    /**
     * Composite prefix (e.g., "East", "East|Enterprise" for multi-level).
     */
    prefix: string;
    /**
     * Map of base column name → full Arrow column name ("prefix|base").
     */
    colNames: Map<string, string>;
}
/**
 * Group Arrow column names by their split prefix (everything before the
 * last "|"). A split exists for a prefix only when every `requiredBases`
 * entry has a non-empty column present for that prefix. `optionalBases`
 * are included when present but do not gate group inclusion.
 *
 * Empty/falsy entries in either base list are skipped.
 */
export declare function buildSplitGroups(columns: ColumnDataMap, requiredBases: string[], optionalBases?: string[]): SplitGroup[];