/**
 * Same default as the widget's buildLayer: an unnamed choropleth key is country.
 * The value is written on the layer, because that is the field the widget reads first.
 */
export declare function choroplethMapType(fieldName: string | undefined): string;
export declare function mapChartPayload(chartType: string | undefined, fields: Record<string, string>, rows: Record<string, unknown>[]): unknown | null;