import { Promised } from "./utils";
declare global {
    interface Generator<T = unknown, TReturn = any, TNext = unknown> {
        /**
         * Groups the elements of a sequence according to a specified key selector function.
         * @param builder A function to extract the key for each element.
         * @returns A collection of elements of the type specified where each element represents a projection over a group and its key.
         */
        group_by<TKey extends string | number | boolean, TElement = T, TResult = [TKey, Generator<TElement>]>(builder: (item: T) => TKey): Generator<TResult, TReturn, TNext>;
        /**
         * Groups the elements of a sequence according to a specified key selector function
         * and projects the elements for each group by using a specified function.
         * @param builder.key A function to extract the key for each element.
         * @param builder.element A function to map each source element to an element in an grouping.
         * @returns A collection of elements of the type specified where each element represents a projection over a group and its key.
         */
        group_by<TKey extends string | number | boolean, TElement = T, TResult = [TKey, Generator<TElement>]>(builder: {
            key: (item: T) => TKey;
            element?: (item: T) => TElement;
        }): Generator<TResult, TReturn, TNext>;
        /**
         * Groups the elements of a sequence according to a key selector function.
         * The keys are compared by using a comparer and each group's elements are
         * projected by using a specified function.
         * @param builder.key A function to extract the key for each element.
         * @param builder.element A function to map each source element to an element in an grouping.
         * @param comparitor A comparitor function to compare keys with.
         * @returns A collection of elements of the type specified where each element represents a projection over a group and its key.
         */
        group_by<TKey, TElement = T, TResult = [TKey, Generator<TElement>]>(builder: {
            key: (item: T) => TKey;
            element?: (item: T) => TElement;
        }, comparitor: (a: TKey, b: TKey) => boolean): Generator<TResult, TReturn, TNext>;
        /**
         * Groups the elements of a sequence according to a specified key selector
         * function and compares the keys by using a specified comparer.
         * @param builder A function to extract the key for each element.
         * @param comparitor A comparitor function to compare keys with.
         * @returns A collection of elements of the type specified where each element represents a projection over a group and its key.
         */
        group_by<TKey, TElement = T, TResult = [TKey, Generator<TElement>]>(builder: (item: T) => TKey, comparitor: (a: TKey, b: TKey) => boolean): Generator<TResult, TReturn, TNext>;
    }
    interface AsyncGenerator<T = unknown, TReturn = any, TNext = unknown> {
        /**
         * Groups the elements of a sequence according to a specified key selector function.
         * @param builder A function to extract the key for each element.
         * @returns A collection of elements of the type specified where each element represents a projection over a group and its key.
         */
        group_by<TKey extends string | number | boolean, TElement = T, TResult = [TKey, AsyncGenerator<TElement>]>(builder: (item: T) => Promised<TKey>): AsyncGenerator<TResult, TReturn, TNext>;
        /**
         * Groups the elements of a sequence according to a specified key selector function
         * and projects the elements for each group by using a specified function.
         * @param builder.key A function to extract the key for each element.
         * @param builder.element A function to map each source element to an element in an grouping.
         * @returns A collection of elements of the type specified where each element represents a projection over a group and its key.
         */
        group_by<TKey extends string | number | boolean, TElement = T, TResult = [TKey, AsyncGenerator<TElement>]>(builder: {
            key: (item: T) => Promised<TKey>;
            element?: (item: T) => Promised<TElement>;
        }): AsyncGenerator<TResult, TReturn, TNext>;
        /**
         * Groups the elements of a sequence according to a key selector function.
         * The keys are compared by using a comparer and each group's elements are
         * projected by using a specified function.
         * @param builder.key A function to extract the key for each element.
         * @param builder.element A function to map each source element to an element in an grouping.
         * @param comparitor A comparitor function to compare keys with.
         * @returns A collection of elements of the type specified where each element represents a projection over a group and its key.
         */
        group_by<TKey, TElement = T, TResult = [TKey, AsyncGenerator<TElement>]>(builder: (item: T) => Promised<TKey>, comparitor: (a: TKey, b: TKey) => boolean): AsyncGenerator<TResult, TReturn, TNext>;
        /**
         * Groups the elements of a sequence according to a specified key selector
         * function and compares the keys by using a specified comparer.
         * @param builder A function to extract the key for each element.
         * @param comparitor A comparitor function to compare keys with.
         * @returns A collection of elements of the type specified where each element represents a projection over a group and its key.
         */
        group_by<TKey, TElement = T, TResult = [TKey, AsyncGenerator<TElement>]>(builder: {
            key: (item: T) => Promised<TKey>;
            element?: (item: T) => Promised<TElement>;
        }, comparitor: (a: TKey, b: TKey) => boolean): AsyncGenerator<TResult, TReturn, TNext>;
    }
}