import type { ChannelAccessorContext, ChartValue } from './types.js';
export { quantile } from './transform-reduce.js';
export type TransformAccessorContext<TDatum> = ChannelAccessorContext<TDatum>;
export type TransformField<TDatum, TValue> = {
    [TKey in Extract<keyof TDatum, string>]-?: NonNullable<TDatum[TKey]> extends TValue ? TKey : never;
}[Extract<keyof TDatum, string>];
export type TransformAccessor<TDatum, TValue> = (datum: TDatum, context: TransformAccessorContext<TDatum>) => TValue;
export type TransformValue<TDatum, TValue> = TransformField<TDatum, TValue> | TransformAccessor<TDatum, TValue>;
export type TransformValueOutput<TDatum, TValue> = TValue extends keyof TDatum ? TDatum[TValue] : TValue extends TransformAccessor<TDatum, infer TOutput> ? TOutput : never;
export type TransformKey = ChartValue | boolean | null | undefined | readonly TransformKey[];
export interface TransformLineage<TDatum> {
    readonly source: readonly TDatum[];
    readonly sourceIndexes: readonly number[];
}
export type TransformGroupSpec<TDatum> = TransformField<TDatum, TransformKey> | Readonly<Record<string, TransformValue<TDatum, TransformKey>>>;
export type TransformGroupRow<TDatum, TBy> = TBy extends Extract<keyof TDatum, string> ? Pick<TDatum, TBy> : TBy extends Readonly<Record<string, unknown>> ? {
    readonly [TKey in keyof TBy]: Extract<TransformValueOutput<TDatum, TBy[TKey]>, TransformKey>;
} : Record<never, never>;
export type TransformOrder = 'ascending' | 'descending';
export interface TransformOrderOptions<TDatum> {
    orderBy?: TransformValue<TDatum, ChartValue>;
    order?: TransformOrder;
}