import { PipeOperator } from '../../core/pipe-operator';
import { ObjectFields } from '../../types/utils';
export declare function chain<TObj1, TField1 extends ObjectFields<NonNullable<TObj1>> & string, TField2 extends keyof NonNullable<NonNullable<TObj1>[TField1]> & string>(field1: TField1, field2: TField2): PipeOperator<TObj1, undefined extends TObj1 | NonNullable<TObj1>[TField1] ? NonNullable<NonNullable<TObj1>[TField1]>[TField2] | undefined : NonNullable<NonNullable<TObj1>[TField1]>[TField2]>;
export declare function chain<TObj1, TField1 extends ObjectFields<NonNullable<TObj1>> & string, TField2 extends ObjectFields<NonNullable<NonNullable<TObj1>[TField1]>> & string, TField3 extends keyof NonNullable<NonNullable<NonNullable<TObj1>[TField1]>[TField2]> & string>(field1: TField1, field2: TField2, field3: TField3): PipeOperator<TObj1, undefined extends TObj1 | NonNullable<TObj1>[TField1] | NonNullable<NonNullable<TObj1>[TField1]>[TField2] ? NonNullable<NonNullable<NonNullable<TObj1>[TField1]>[TField2]>[TField3] | undefined : NonNullable<NonNullable<NonNullable<TObj1>[TField1]>[TField2]>[TField3]>;