import { IndexedSelector } from '../IndexedSelector';
import './defaultIfEmpty';
import { EqualityComparer } from '../blinq';
declare module '../Enumerable' {
    interface Enumerable<T> {
        leftOuterJoin<T, TInner, TKey, TOut>(this: Enumerable<T>, innerSeq: Iterable<TInner>, outerKeySelector: IndexedSelector<T, TKey>, innerKeySelector: IndexedSelector<TInner, TKey>, selector: (outer: T, inner: TInner | undefined) => TOut, equalityComparer?: EqualityComparer<TKey>): Enumerable<TOut>;
    }
}