import { DuckDBDataChunk, DuckDBType, DuckDBValue, DuckDBValueConverter, JS } from '@duckdb/node-api';
/** Never receives null; the caller short-circuits those. */
export type ColumnConverter = (value: DuckDBValue) => unknown;
export type Transform = {
    names: string[];
    converters: Array<ColumnConverter | null>;
    objectShape: Record<string, unknown> | null;
};
/**
 * Renders epoch millis as an ISO timestamp, matching `new Date(millis).toISOString()`
 * byte for byte across the whole range Date accepts, expanded years included.
 */
export declare function formatIsoFromMillis(millis: number): string;
/**
 * Recursive converter for nested types (LIST, STRUCT, MAP, ...), where the legacy driver
 * kept JS built-ins. Nested cells go through the very same converters as top-level columns,
 * so a TIMESTAMP inside a STRUCT is the same ISO string as a TIMESTAMP column.
 */
export declare const convertNestedValue: DuckDBValueConverter<JS>;
export declare function getColumnConverter(type: DuckDBType): ColumnConverter | null;
export declare function buildTransform(names: string[], types: DuckDBType[]): Transform;
/**
 * Column-major: each vector is decoded once and its converter is picked once, instead of
 * dispatching on the type for every cell.
 */
export declare function transformChunk(chunk: DuckDBDataChunk, transform: Transform): Record<string, unknown>[];
export declare function convertDuckDBParams(values: unknown[] | null | undefined): DuckDBValue[];
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